If you take an antihistamine to stop the production of snot and a decongestant to help drain, and tylenol or the like to help inflamation, that will help as well. (my cocktail when I get a sinus infection which was every year I lived in San Diego) Drink plenty of water.
Also, put a bit of Vicks in some boiling water in a bowl, put your head over it, cover with a towel and inhale. It will help.
Do your teeth hurt? That is a sure sign of a sinus infection.
I think green snot, and lasting longer than 5 days to a week, see the dr. If you have a really bad infection, sometimes it takes more than one round of antibiotics to penetrate because the sinus tissue is so dense.
Sinus infections suck.