Lay on your left side. It's great for circulation. Also drink lots of fluids and make sure your room gets a lot of air circulated through it. If both nostrils are congested. When this happened to me I would lay on my back. Or stand up and bend over forwards a bit and then tilt my head up backwards.
I've been taking a Tylenol sinus and decongestant per recomondation of my dr, was also told to be sure to drink lots of fluids to help break up the congestion.