What to do:

First....Don't panic, you can do this! And don't hesitate to delegate tasks to dependable people!

Before the night :

Work out which style quilt you would prefer and all the specific details to go with that.
Work out your date
Work out the venue - the combination of a dining room and reasonable size lounge room would provide adequate space for most parties. If not, consider hiring a small hall or meeting room, at your local church maybe.
Work out what you need to ask guests to bring, usually that will just be fabric scissors if they have them (emphasis the "fabric" bit, you do not want ordinary scissors!), a favorite needle if they want and a lamp if their eyesight causes them any issues.
Send out your invitations in plenty of time (specially to anyone interstate or overseas! )
Consider asking one or more people to be assistant teachers on the day. They just need to know how to sew a basic running stitch, they need to be really nice people who will be encouraging to everyone they're helping and be able to get together with you before the night for a practice run with making a block (so their not doing it for the first time at the party, helps them to be better equipped to help others!) as well as to run through the list of hints and tips for Patchwork Parties that I've included below.
Think about the lighting available and take any steps necessary to improve it for the night i.e. lamps, brighter globes.
Make a sample block or 2 and if possible, also a semi pieced block or two that will show people steps along the way and not just the final result.

At the party you will need:

Needles (enough for everyone and a few spares, I've found size 9 "betweens" to be a good size for most people but be sure to have a few a little larger...those aging eyes issues!)
fabric scissors (1 between 2 to 3 people can work ok...don't forget to count in those who can bring some along!)
threads (please indulge and buy quilting thread ie Gutterman quilting thread, it's waxed and will be pleasantly co-operative for people to use, well worth the minimal extra): 1 reel to 6 people works fine in terms of traffic flow :o)
templates (you can get away with 1 between 2-3 people and they can be made from cardboard, milk bottle plastic or template plastic - purchased from a fabric/craft store)
Sandpaper sheets - fine grade (one for each person - these go under the fabric as they trace around the templates to stop the fabric from shifting)
Grey lead pencils (HB - one for each person)
Pins (I have found the bead headed pins the most practical - household pins are both too thick and hurt your fingers after a while. The beads are kinder to your fingers and the thinner pins are kinder to the fabric.
All fabrics that you are providing for the patches/blocks. Including any fabric that has been mailed to you by anyone who can't be there
A label for everyone present to sign which will be sewn onto the quilt later (a plain, pale homespun or calico fabric is best - if you don't know what these are, just ask at your fabric shop, they'll be happy to help).
A small cork board to hold the label (pin it to the corkboard with a sheet of sandpaper underneath so it's stretched and stays steady as people sign) and fine tipped fabric pens for signing (see in the craft section of your local store)
Chop up new sink sponges to become tiny impromptu pin cushions (again 1 between 2 is fine)
An iron and towel to iron on (if not at home)
Refreshments (really simple ones ok! There's enough happening already to take your attention! Or delegate the task to someone else, better still, ask everyone who can to bring a plate of goodies with them...we did this for Levi's Patchwork party - our 5th child - where there were nearly 50 people and it worked really, really well!)

Your guests bring:

Willing hearts and hands
Unless you are choosing all the fabric that is going into the quilt (I realize that some of us just can't handle not being in total control of colour schemes!) your guests will bring the fabric they have chosen (quantities will vary depending on the type of quilt but they will be quite minimal, (i.e. between 1 and 3 lots of 50 cm x 50 cm).

Hints and tips for Patchwork Parties

Hints and tips for the Invitations

Hints and tips for the Guests

1. Hints and Tips for Patchwork Parties

Using the demo blocks, run through briefly how their pieces will come together in stages and what the final result will look like, this will really help the visual people.
Word people up on which lines will be cutting lines and which will be sewing lines!
Let them know about the selvedges (Edges of the fabric with tiny holes in: where the printing machine has held onto the fabric. Usually about going to about1cm's depth from either edge.) and to trace a short distance from them and to line up their squares with the grain of the fabric.
Tracing on the back of the fabric, not the front!
Pinning: It’s really important that they match up their seam lines carefully and pin through corner to corner (especially for any of the central seams, the outer seams will be more forgiving)
When making the two large triangles which will then make the square, if you sew your smaller triangles in identical sequences then when you flip them to join them into the square the patterns will reverse just like you need them to.
Encourage people to check on both sides as they’re joining fabric pieces that they are sewing through and not over or under the seam lines. It’s too easy to only check this after and then have to redo the stitches.
Suggest that people only have about 30 cm’s of thread otherwise they will find the thread tangling. Assure them they will only need a little at a time and won’t come up short.
When people press the seams, ask them to press towards the darker fabric (you’ll probably have to demonstrate- use a demo block for this)
Show them how to start and end their stitching by starting a few stitches back from their corner (backstitches) and going back by 3 or 4 stiches at the end etc. Also let them know that they won’t be sewing edge to edge but will be staying on the seam lines. Tell them that edge to edge is when you’re machining.
Encourage them to iron after piecing the first two sets of triangles, it will increase the accuracy of the final block because the pinning will be more accurate. The pinning can be something that really throws people at first, use the demo blocks to help with a visual.
Encourage them to lay out their whole block before they piece it in case they find there’s anything they want to change.
Let them know that the blocks will all be trimmed later to match exactly once they’re all finished. Don’t let anyone do it themselves!!

For the Appliqué people

With anyone doing the applique blocks, gently remind them to think about whether there is a particular part of the fabric (picture etc) they want in the circle.

If it hasn’t already been done, they will be tracing a circle template onto the paper side of the fusible webbing.
This is then cut out but about a quarter inch or so outside of the traced line.
Then they iron this over on the back of the particular piece of their fabric they want to focus on - non paper side down. Should the fusible webbing meet the hot side of the iron it won't want to come away in a hurry. It's worth reminding people about this one!
They cut out their circle precisely on the line this time and then take the circle and square of background fabric back to the iron, peel off the paper, position it exactly with the glue side down and then iron it until the glue is melted.
Now it’s ready to embroider.

2. Hints and tips for the invitations:

Be *really* specific about the colours and feel that you want for your quilt (I cannot emphasis this enough; you will always get one or two people who still manage to bring something quite different to what you've asked for, but in my experience it can be fudged really well when it's only one or two, so don't stress at the potential!)
Make sure you mention how much fabric they need to bring (you may like to recommend one or two fabric/quilting stores in the local area)
Mention about the fabric scissors, needle and lamp (if you feel it's appropriate - not everyone will have vision issues)
Give a deadline for mailing fabric to you, that helps those who are compulsorily late to get it to you on time! :o)
Emphasize that they (as in the guest) are not required to be a sewer - Anyone CAN do this! And it's fun and feels good to have been a part of such a special gift and time of community.

A sample Invite:

A "Your Surname" Baby Shower Patchwork Party!

Dear

We would love you to come and be part of creating a Patchwork Quilt to celebrate our "April 2003" baby. You do not need to think of yourself as a sewer to be a part of this! There will be plenty of help, afternoon tea and a great atmosphere. If you won’t be able to join us, we would be really blessed if you could still send fabric by mail to be a part of the quilt. We’ll make up your block for you, include it with the others and make sure your name is on the label on the back.

What to bring: (What follows was a description I put together for this quilt specifically but it might give you ideas for wording) Our plan is to make a traditional scrap quilt with mainly four inch hourglass blocks and some simple applique blocks. It will have a country feel about it (as opposed to a modern feel) and so we ask if you could bring a darker/strongly toned cotton fabric in either a blue, green, brown or warm red (checks and patterns/pictures are fine) as well as a lighter cotton fabric to contrast (creams and pale colours are fine but no whites please unless the white is the non dominant colour in a pattern, and again checks and patterns are ok). The fabric needs to be 100% cotton (not drill cotton, it's too thick to work with), a minimum of either 20cm off the roll or 40cm by 40cm square, washed and ironed. ( In most shops you can also buy "fat quarters" which are 50cm by 50cm ready cut and bundled) It would be helpful if some of the leftover fabric can remain with us so that extra blocks can be made as needed to complete the quilt to size.

If possible could you bring a small plate of afternoon tea to share, fabric scissors if you have them and if you feel it would be helpful for you, a lamp and extension cord (please phone first as there may already be enough there).

VENUE:

DATE:

TIME:

We hope you can join us for this special celebration.

Love from "................."

RSVP (your name and ph #, e-mail address) by (date) and add this "but sooner is better-lots of planning to do!" in brackets

Or mail to: snail mail address

3. Hints and tips for the guests:

Hints and Tips for the guests: things for you (and any assistants) to be sharing with them before and during sewing to avoid unnecessary hassles

Length of thread should only be about 30 cm otherwise you risk it tangling consistently.
How to make several stitches at once.
Press the seams toward the darker fabric where possible.
How to backstitch when you reach a pre sewn seam and then go through the seam rather than over it to get to the other side.
Take your time when lining up and pinning two pieces of fabric- it’s so worth it. Don’t be afraid to do it a few times until your happy with it.
Check for directional fabric (i.e. if it is directional - has a definite top and bottom - they will need to make decisions about where to trace their templates very carefully so they get a symmetrical result with the pattern after the block has been pieced).

Specific tips for specific blocks:

On the Hearts Quilt

6 ½ " block with right side up and the 2 large and 2 small squares which become the triangles need to be face down.
Check for directional fabric (ask me how I know! :o)