you need to grab a chair and just take a seat man, this game is a long one. while in pots that size they will need to be watered with about 1-2 cups of water every 2-4 days. if the soil looks dry then put your finger in to check, if it feels dry then water it. if it feels damp, check it when you wake up the next day and proceed as needed.
it's best to keep your fan on all the time if possible, but you can run it a few hours a day and get by as long as the temp doesnt get too high, buy a thermometer if you need to, you will never guess how cheap they are at the .99 store.
use glossy paint, but if you want it to be even easier, go to an arts/crafts store (or somewhere else) and buy a few sheets of white posterboard. where i am you can go to Michael's, they come with a glossy side and flat side, just put them in your trashcan and they will take the same shape, tape them in if you need to. Glossy side towards plants.
weed plants are pretty hardy, meaning they generally strong and will cope with their growing environment if it's not freezing cold or a burning hot. you are giving them some good conditions, all you have to do now is watch.
read the thread in my signature called Grow Journal w/ Pics....I started out very similar to you, and you can see everything i used, everything i did, and best of all the shit ton of pics i took. happy growing my friend.
last question, if you are at a homies house, why are you doing a little trashcan grow? make him clear out his closet
