Oral sex help!

So my boyfriend and I have been dating for 3 months now. We're really close and he's amazing don't get me wrong. The sex is great. We both agree on that. However I can't seem to please him orally. I've never had this problem before. I'm 19 and have been with 5 guys including him, 3 of which told me I gave them the best head of their life. I know he's been with his fair share of hookups (45 and he's 24) he told me only 2 ever gave him "decent" head. So I know hes picky. But nothing feels worse than being bad at something in bed! Any tips/advice please?