For racers, they train to spin at a pretty high cadence, which allows for power and speed while still allowing for endurance.

It takes practice to retrain your legs to spin faster. Also, you have to learn what your natural cadence is. Start by riding as you would, then whatever that gear is, shift 1 lower. Get use to the feel of that.

For me, I am likely somewhere just below the 90 mark. Works for me. I have, basically, better slow twitch muscles, less fast twitch. Not much of a sprinter, but I can ride all day long.

My son use to pedal very slowly. On a few rides I had him try a lower gear for more spin. He now spins better and does not get as tired out, and still goes pretty fast.

As you train and practice, you will discover your ideal cadence. When you do find your ideal, I believe you will know it - you will be riding along, feeling pretty fast and not feeling like you are really exerting much effort - at least that is how it is with me.