well for starters u shoud dress as alice (if u werent going to already) get some thigh/knee high striped socks, those school type shoes, etc.
wen u decorate consider using cards and chess pieces, clocks and mirrors, maybe find a painting/picture of an owl (i dont no if uve read the books or not).
maybe find some white rabbit soft toys? and any animals like mice and birds, or set up certain animals together like a lion and a unicorn together with some cake?? and a walrus and a carpenter looking doll and some oysters??
u could set up some sort or race thing (maybe more a scavenger hunt or clue finding activity) and call it a corcus race?
american mcgees alice is definitly a good idea to get some inspiration from.
u could maybe play croquet and maybe make some fun thing out of it? depends how creative u could b?
well thats all my ideas for the moment, hope u could get something out of it lol
if u have any pets u could maybe use them, but remember to b nice to them lol