I was doing a flight with the ATR 72 a little bit ago, and I had the fuel condition lever on low idle to attempt to keep the plane from rolling. Well, I forgot to put it back on high idle before take off and crashed. I got airborne finally, and then couldn't figure out why I was not gaining airspeed. That's when I realized my error. Then as I was passing through FL 220, which was supposed to be my cruising altitude, I realized I had another problem. I couldn't figure this one out. So, I ended up having to check the Avionics switch and Generator switches, and then make a quick descent to keep from stalling. Nothing like the stall warning horn blaring at me to get my attention. I finally leveled off at Fl210, and things went great. Jordan