when your nostrills are blocked due to mucus mebrane

First take some pure water and little salt, and make a solution not so salty.
lay down and pour that saline water into nostrils in very low amounts till both your sinus cavitis and nostrills are full. meanwhile try breath through your mouth only.
  keep the solution inside as long as you feel comfortable. finally when you are squuezing your nose do not ever do it forcibly(this is very important else you will end up in a life time vision loss or hearing loss ). The membranes inside head are very sensitive. so never blow your nose forcibly.


   when nostrils are free from blocking try the following whenever you have time.

  Do yoga or breathing exercise or jog for some time in the meadows. This will pump the oxygen into your blood causing the membranes full of energetic oxygenated blood and cause the nasal septum membranes to relax for free air passage.