well since nobody decided to directly help ya, here ya go:
1. make sure your thumb is positioned on the top when your hand is wrapped around. best way is usually to lay next to him if your just giving a hand job.
2. do not bend the penis down or side to side more than 45 degree angle, this can hurt sometimes.
3. When "stroking" dont squeeze too hard, make sure you are squeezing enough to have a good grip, but no more.
4. if you can rub the back edge of the head a little that helps, but do not irritate it, you will need feedback form him on this part.
5. a handjob will take a while to cause him to ejaculate, so you might wanna start lifint weights to beef up your arms.
6. finally do your best not move it around alot when stroking, it will be harder the faster you go, but just try and keep it steady.
Thats the best I can do for ya, hope it helps. lol might wanna post this as a handjob tutorial