You're not alone in this fear. Most men will agree that approacing a woman is one of the most stressful things they have to do.
You may not realize it, but the reason you get nervous is because you have a fear of rejection. You don't want to experience the embaressment,
so you don't bother approaching her in the first place.
There are a few key points you should learn:
1. Don't hesistate approaching women.
You have to learn to build your confidence and just "man-up", otherwise you'll end up spending your night alone, again.
2. Prepare for any possible outcome when you do approach her.
She may be interested in you, or she may not. The point is, at least you tried. The big issue here is this is where most guys give
up if they get rejected. You can't give up. Just take the loss, move on, and find someone else.
3. Create opportunities through flirting.
So you've approached her...OK, now what? Well, now you gotta talk to her obviously! Use good body language. Look relaxed, smile, say hi, and then carry on. If you really wanna take your flirting game to the next level (i.e. what do I say after "hi"??) I recommend The Flirting Formula. It's not full of stupid one-liners that will have you surrounded by women, but it has good conversation starters that the both of you can engage in and have a good time. You can read the review of it here
4. Don't use cheesy pickup lines, or any pickup lines at ALL for that matter.
5. Keep your eye contact on her EYES and not anywhere else, if you know what I mean.
I hope that helped you out, good luck!