Maybe this could help you:
1. First you need to get him turned on - be more aggressive, grab his stuff, slowly massage his balls through his pants, it's important that you act as seductive as possible - the more you're turned on - the more he'll be turned on. Pull his pants down slowly and act as naughty as possible - this is a great turn on.
2. Grab his hand and lick on his fingers slowly before you give him head - just put his middle finger slowly into your mouth and suck on it, up and down, slide it slowly and moan - you have to moan a lot so he feels like a king.
3. As you're licking one finger, slowly start stroking his shaft (penis) with your other hand, you have to be on your knees and he should be standing, look him in the eyes - this way you can see his reactions. You need to love giving him head if you want him to really enjoy it.
4. Most girls make the mistake of being too soft - don't do that, grab his penis tightly and stroke it hard, as you're twisting his shaft with one hand slowly start sucking on the head (the tip) of his penis, curl your tongue around it, twist it in circles, then point it upwards and slowly lick it while you're watching him.
5. Say something like "mmmmm I love it" then smile, smiling is very important - it conveys that you love it. Keep on stroking and sucking harder.
6. Start talking dirty to him, put your hands around his balls and tickle them gently - make sure you are gentle 'cause his balls are very sensitive, as you're tickling, keep on stroking and sucking.
7. Once you see that he's getting closer start stroking harder - and don't even think about slowing down. Scream at him, tell him you want it - tell him where you want it (swallowing will make him go crazy just as you want it) - then as he starts to come, you have 2 options - you can hold his penis or he can hold it - I suggest you let him hold it and squeeze it out.
8. Then hold his penis and stroke it slowly, just as if you were trying to squeeze every last drop out of him into your mouth, give it a few more finishing licks.
9. Then smile at him, open your mouth and show him what you've got in your mouth, smile, then swallow all of it - then look up at him again and open your mouth to show him it's gone. If you REALLY want to learn how to give a blow job then you have to read Jack's Blowjob Lessons ----> link
10. Smile again, believe me he'll love you for it.