like they said, concentrate on good pedaling and time. distance will come (speed is just a factor of time and distance). try to imagine your feet making triangles with the cranks instead of cicrles. the tip of the top of the triangle is at the top of your pedal stroke (12 o'clock). the bottom right is at 5 o'clock and the bottom left is at 7. helps smooth out the pedal stroke. it'll feel quirky/uncomfortable pulling up while pedaling at first but it'll help efficiency.

any speed is a good average speed as long as you're riding. usually average speeds arn't compairable because of outside factors such as wind, hills, etc.......

when you become more comfortable on the bike, pretend you're driving a car when it comes to road rules. make sure to signal and let everyone know your intentions. for now do what you feel comfortable with