I started with the corners of the room and then worked my way to the reflection points and the wall behind the speakers. It's fairly easy to determine where or what you need by playing some music and walking around the room. In an untreated room you will get bass build up in the corners for example. Also, if you do the "clap" test and get echo, that's bad. You may not have to treat the ceiling if you have carpet and rugs on the floor, but with hardwood the ceiling will need treatment. I have had good luck with Acoustimac. There products are well built, the service has been excellent and there are many color choices. I like bass traps with the tapperd sides for example.
Room Treatments
Whats the best method of treating our room. Sometimes I believe we make allowances in our rooms for inadequate recording studios. Should we be trying to obtain the best sound or the exact duplicate of what we believe was recorded. The only steps I take is to insure I have the proper speaker placement and that has taken me almost a year. Im not sure Im right but I try to acheive the sound that is most pleasing to my ears. How about you.