Instead of using a nasal decongestant pill such as Sudafed, try using a decongestant nasal spray like Afrin or Anefrin.

It is worth noting that nasal sprays containing oxymetazoline (the active ingredient in Afrin and Anefrin) should not be used for extended period as they cause rebound congestion ie if you use it for more than 3-5 days, when you cease using it you may become congested for a number of days.

I agree that sinus rinses are good. I tend to mix salt with lukewarm water, as it is the least irritating. I have read you are not meant to use tap water as it is not sterile and can put you at risk of infections of the central nervous system, but afaik data related to this is pretty limited. Due to the insufficient amount of evidence and the potentially severe consequences, it is likely safer to buy over the counter saline preparations or boil your water first.