what should my PSI be when im up on plane it is about at 10 PSI. dose that sound right, should I have more or can I have less??? And about how far can I trim my motor all the way down then when I get on plan I get it about half way can I bring it up more or is that good.

Depends on the motor.  Most Johnson's/Evirudes need to see 16 or better.  Can't say much for what the black motors require, your dealer should be able to supply you with a number.  Sometimes the owners manuals have that.  

You should be able to tell by the feel of the boat.  As you trim out, the bow should lift a little more each touch of the button and the boat should gain a little more speed.  If the boat gains rpm and not speed, you have trimed too far and the prop is starting to cavitate, bump it back down slightly.  If you listen, you can hear a difference in the sound and sometimes you can feel it in the steering wheel.  Just how much you can trim out will be determined a lot by the prop you're running and how much bite and lift it has.

Ben is right on. All too many over trim. I tuck the motor all the way under and put the throttle to it. After I come out on plane I back the throttle off a bit as I recall back to about 4000rpm's but stay on plane then I start to trim out with just a tap or two at a time. At least with my boat when it is at the proper balance of throttle and trim there is a noise change. I don't know how to describe except to say it is "sweet". When I hit this sweet spot there is no steering torque from that throttle setting to full throttle. Away I go!