^That gives you some specific details to focus on. But the biggest tip I can give? Even if you hate giving a guy head, pretend to love it.
Fake it with the best of them. Because even if you really don’t like the act itself, you do enjoy giving someone else pleasure, so it’s all the same in the end.
Go to town on his dick like it is the best fucking popsicle you’ve ever tasted. Lick, suck, tease, bob, play with him, do EVERYTHING. In fact, act like it’s your new favorite toy and it’s yours to do what you want with.
Your enthusiasm and passion is half of his pleasure. If he thinks you love his cock that’s going to turn him on 10x more than any trick you’ve got with your mouth. Just the truth.
One more thing? Different guys like different stuff, so don’t make the mistake of doing “one style fits all”. Ie. some guys like you to start off slow and teasing, then go for it with gusto. Others want you to skip the teasing and jump right into the swing of it. Some want this fondled, some want that touched, and so on. There’s no ONE way to give a blow job. Listening and being aware of the other person’s responses and reactions is the best way for you to learn what pleases them the most and therefore give them the best head possible.
Go forth and suck!