If you want to be a good cocksucker, I think you need to pay attention to and then apply what feels good when someone is sucking your dick. It also helps to pay attention to the guy you're servicing, he'll let you know if he likes what you're doing or not. After all, what really turns on one man might turn off another.
Ultimately, I think what makes a good cock sucker is that they love and thoroughly enjoy what they're doing. When I'm sucking someone's dick, I'm enjoying every moment of it and it really turns me on.
And, as always, practice does make perfect.
