Interfacing Troubles

"Interfacing is one of the steps that can leave the most confident of sewer worried and the novice terrified." -Sew News. All of a sudden, I am having the worst luck with fusible interfacing. On my last couple of projects, once I have applied the interfacing, the fabric side has bubbled. Each project used a different type of interfacing, so I have decided it is not just a bad piece of interfacing. I have researched the problem so I am currently trying to solve whatever it is that I am doing wrong. I bought most of my interfacing off the bolt, so I really did not get any directions included. My first try is going to be to decrease the heat on my iron with steam and without steam. I am also going to try pre-shrinking by both soaking the interfacing in hot water and air drying, and steaming it with a hot iron. I guess my fusible interfacing has just decided it is time to test my problem solving skills. As my mother always says, "If you want to learn patience, sew."