New grow room

Hey
i just finished my attic grow (don't do it)
it was a complete waste of time
way to hot and humidity was abotu 80% 24/7
any was i had an old cupboard sitting in the garage
and now its time to set it up i need help with vetalation because i am using a 400w MH and the space isn't big.
dimensions:
1 and a half ft wide
2 ft deep
4 ft tall
cheers guys.

i would blow air directly out of the top, with a passive intake somewhere near the bottom , with a 400watt in that area you are going to have to pull some mad cfm's of air, which is going to create a nice little windtunnel in there.

I got an exhaust fan from my bathroom
and i might buy another one to suck air in.
also i have read that getting a bottle and putting yeast, suger, glucose and water is a form of creating Co2
is that right and will it help at all?