I've been "spinning" since spinning started - quite a few years ago.

First make sure you use a heart rate monitor. You can get one fairly cheap. Know your target zones (depends if you are spinning for "fitness", "fat burning" etc) and stay there occasionally allowing your heart rate to go towards the higher end.

Also tension is a personal thing. My opinion, since I am a cyclist and spin as a supplement to cycling, I try to keep the tension so I am spinning or riding as close to the way I do on the road as possible. That's not to say you won't have alot of tension on the bike to stimulate climbing, but keep in mind, when I hit a steep hill on my bike, I lower my gearing, think of that while spinning.

Also it really is more important to work on proper form then it is to get that tension up all high. I see so many people in class with the tension on too high, and their form gets all funky. Elbows bent and bouncing, knees sprayed out, back too upright. Again think about your form on the bike. Your pedal stoke should be smooth and even, elbows bent and in close to your body, shoulders down, back straight, no bouncing!!!

Start out slow. No need to keep up with the class. Just stay on the bike and spin, get a good workout and as it gets easier ( and it will) then push up that tension.

Have fun, I love spin class especially with a good instructor and good music (which is generally rock, not disco and not too loud. Loud music will send me out of the class).