In general you want your cadence to be in the 80-100 range. Different people have different natural cadence at which they feel the most comfortable and it does take some work to move it up. My comfort level is about 85 and I have progressively moved my cadence up to the 90-95rpm level.

It is easier to do this if you are using clipless pedal system or toe clips as you are more engaged with the pedal. Also focus on keeping your cadence high and shifting gears to keep it even. If you are going up hill just shift so that your cadence does not change, same for going down hill. Riding with wind is a bit more difficult since gusts will slow you down and you cannot really pick a gear for the gusts since it would probably mean it would be too low most of the time. Having drop bars helps since you can get low and cut the impact of the wind which means the gusts will have less effect. Last get a cheap computer that does speed and cadence and if you can HR.

Mainly focus on your cadence and HR and as you improve your fitness your speed will naturally increase with the same HR and cadence.