My driver's window is loose (when the door is open you can see a gap between the weather stripping and door) and it rattles when the door is closed with the window not all the way up.

What should I look for/what do i need to tighten to get my window nice and tight?

Also the same door is sagging a little bit, should I just check and tighten the brackets that connect it to the car?

Is there anything else I should check that commonly comes loose in there over time?

 

I had a very simular problem if you remove the inner door panel there should be, I think two L shaped peices of metal with felt on them. with the window up you can adjust them to apply pressure to the glass. they loosen up over time or were never installed rite from gm