last minute party advice needed please

[taytotayto]

i wasnt going to have a birthday party for dd's first birthday, i know that sounds mean but dh has talked me into it and we have about 20 (adults and children) coming. its our first party!!! and i have no idea what quantities ill need and what ill need. im trying to do it on the cheap!!
(im making the cake.)
anyone got any advice.
thanks x

I did (about the same amount of people):

Sandwiches - 3 baguettes (cheese, ham and tuna mayo), 1/2 loaf brown bread
3 x quiches
1 bowl of tuna pasta
1 bowl of pasta with pesto
salad
sausages and sausage rolls
juice
bday cake

There was far too much food and we took the leftovers to another party that evening!

If it's still a summery day you could turn it into an informal barbecue. Most children (and adults for that matter) will happily munch a sausage and some french bread if there's a jelly and some ice-cream afterwards. Salads and relishes for the grown-ups. If you go with paper plates there no washing up at the end either!

If it's an indoor party there's really nothing wrong with trays of sandwiches with tasty fillings, crudites and dips, maybe some ready-made samosas & other savouries for the grown-ups.