The wonderful memories from the past, thanks to that beautiful girl
 

A bad blow job starts with sucking and scraping against the clitoris right away, or even using your teeth. A more common misunderstanding is thinking "licking the spot" means "sticking your tongue inside the hole," leaving the clitoris untouched, so she only feels being stimulated but not really getting off.
The key to oral sex is getting your partner wet, starting slow and building up, maintaining a steady rhythm, and listening to her body language and breathing.
Here's a quick tutorial we came up with with my girlfriend.

Sucking snails, dogs drinking water, licking plates
 

First, get your mindset right. Tongue kissing can happen anytime - generally during foreplay to get the girl into the mood quickly, or even to help her reach orgasm. Or after she comes, once you're both exhausted from thrusting, you can end with tongue kissing - that works too.

For many girls, clitoral pleasure is more direct than deep vaginal stimulation. The clitoris is the most important erogenous zone, and this is really important. Everything below her can make her feel good, but the clitoris is especially sensitive, and you really need to stimulate it.

If you just rush into thrusting, she's likely to feel like "being penetrated but not really getting off," which isn't a good feeling at all. You want to send your partner soaring, not leave them unsatisfied - unless that's what you're trying to do on purpose.

Porn videos cut out foreplay because the cameras need efficiency. You really shouldn't copy that. A real person's clitoris and entire vulva need time to become engorged, wet, and open up. It takes your patience, your guidance, and your erotic conversations.