She's never gonna be great if she doesn't like it.Period.I love giving head.I'm pretty fucking great at it.Why? Because I love it. However...not to be mean, but are you scrubbing things up before head?Make it nice and fresh, and she'll like it more. DON'T hold her head down when she wants to come up for air,or jam it down her throat if she doesn't like that.
Try some thick caramel ice cream topping.It takes a while to lick off,thereby stimulating salivation.And it tastes good.Don't have her learn from a porno...most of those girls don't know how to suck a cock, and that's a fact.There are a few, but not many.
Have her start by running her tongue around it and exploring it....TELL her how good it feels when she hits a spot that is particularly sensitive. If she can't take all of it in her mouth, she can use her hand as an extension of her mouth, stroking up and down in unison with her lips.If she uses too much tooth, have her fold her lips over her teeth firmly...it creates a ridge that can be used to stimulate the head in a really good way.Have her change up...don't just go up and down, you turn and twist your head slowly, vary speed and pressure. Press the tongue along the vein on the underside,swirl it clockwise and counterclockwise around the shaft as you go up and down.(just trying to help, sorry if this is too graphic for ya).
As for deep throating, I personally have no problems...but some girls are gaggy. One way to help with this is to make more room in the back of your throat by sticking your tongue out slightly while depressing it in the back.You can lick the balls at the same time as you have the penis in the back of your throat this way. As you get more and more used to this,you can use the muscles in the back of your throat to stimulate the head...slightly try to close your jaws in the back (SLIGHTLY!!),creating a tighter seal...twisting the head back and forth as you do this feels really good to guys.You can flex your throat like you're trying to swallow...just make sure you took a good deep breath first,lol. Moaning deep in your throat can produce a vibrating sensation some guys like.
MOST important is to ask what your partner likes.Everybody is a little bit different.If your girl doesn't like doing it,she's NEVER going to be as good at it as someone who really enjoys it.Lack of enthusiasm is a turnoff.If she likes getting eaten, try doing the 69 position...every time she makes you feel good, return the favor.
I also personally like a guy to lie back, sometimes with a pillow under his butt,with me between his legs.I rarely do the traditional sit down blow job.On a bed, we're both relaxed. With his legs apart and me between them, I can have my upper body resting on my elbows,and I can pull the penis downward slightly...it creates resistance, pressing the head against my palate slightly,and as I go up and down, he feels the bump at the roof of the mouth pressing against it...who needs a tongue ring?You can also use your hands to cradle the balls if he's into that,stop and kiss his inner thighs and nibble them,caress the pubic area.
Hope this helps.