+1

Your seat should be high enough that your leg is very near full extention at the bottom of the stroke. If you rock in the saddle you have gone too far.

Cadence should be between 90-110 rpm. Get a computer that shows cadence. After you become experienced you probably won't look at the cadence feature anymore, but it is invaluable during the early days. Also, if you don't have them already, you will need clipless pedals in order to turn a good cadence.