Be sure that the duct coming into your room is not blocked (I once found a stuffed animal inside an air duct), and that the cover for that duct room is fully open. You may be able to force more cold air into your room by closing the registers going into the other rooms. This can work well, especially if another room is too cold, or is mostly unused.
It may also make a difference whether you keep the door to your room open or closed; try it both ways.
If you are running electronics in your room, especially computers, turn them off when you are not using them.
If your windows allow direct sunlight to come into your room, be sure to hang heavy drapes and keep them closed when the sun is shining in.
If you do not already have one, install a ceiling fan. It will not actually cool the room, but it can make you more comfortable. Be sure to turn the fan off when you are not in the room, or the running motor can actually add heat to the room.
What direction does your room face? Upper or lower story?
Get more air conditioners.
I live in a duplex in Colorado and it is always hot in my room and we have air conditioning. We have tried portable air conditioners and fans, Neither seemed to make a difference. If you have an affordable way to make my room colder it would be great!
