1) Plan it for when it is NOT nap time. Or the child will be tired/fussy and over-stimulated.
2) parties at this age are typically 2 hours max.
3) To cut costs, plan it for a non-meal time. Then that way you don't have to serve 'lunch' or 'dinner' and can just serve cake and snack stuff.
Also, determine how many people you will invite... this also affects cost.
4) Plan ahead... for setting up of the party and clean-up after ward... and get HELP to do this. Or you will be stuck doing it yourself and then having to contend with baby. And clean-up after ward can take time...
5) Decide if you will open presents at the party or not. Or just at home after the party. If doing it at the party, it can take lots of time, maybe 1 hour. AND have someone help you, with a notebook, to write down who gave what, so you can write proper thank you cards afterward.
6) If doing so, you'd need to plan the opening of presents, within the party's time frame of when it ends.
7) Plan the cake time/singing/eating of the cake, into the time frame too.
8) take lots of photos.
9) Have a banner or huge piece of poster board, for people/kids to sign or put their names/handprints on it... it makes for a nice sentimental souvenir from the party.
good luck,
Susan