Hey buddy, welcome to the forum!
If you are an inexperienced young man, TEN simple but tedious steps can be followed.
1) Embark on a NEUROTIC hygiene routine. Good teeth, NO acne, no dandruff, shave head if you're balding. NEVER FORGET deodorant.
2) Hit the gym for at LEAST six months before making approaches. If you are overweight, cut, if you are skinny, bulk and cut. There are four standard exercises, the benchpress, deadlift, squats, and military press.
3) While you are hitting the gym, buy some material on the art of seduction. They usually have some good techniques. Alot of the techniques are BS, but the lifestyle stuff is spot on. It's also good for learning how women think.
4) When you are in shape, get a female friend to take you shopping, and buy an outfit for clubbing aka sarging. A fitting pair of jeans, nice dress shoes, and some fitting loud dress shirts should work.
5) Get the right haircut and shave. If you have heavy beard, use that to your advantage and do a 3-day beard. If you have the right face, do a buzzed head like the army guys do.
6) Learn how to peacock, which some call displaying your "******". Go the extra mile and get some hot cologne, a cool necklace and slick watch, maybe even get a tattoo or a diamond earring if you're up to it.
7) Take BOTH a martial arts class and a dance class. Body language is EXTREMELY important to girls, and both these improve your body language. You need to be ready to fight because girls want a man who can stand up for himself, and you might run into a meatheaded jerk at a club who likes the same girl as you, and YOU want to come out looking like the Alpha, right? Also women associate dancing with sex, and not alot of guys can dance well, so those who can they notice IMMEDIATELY.
8) BUILD SOCIAL CAPITAL! Join clubs that you're interested in, play sports, do a camping club, get on meet-up.com, as long as you're already good-looking and chill, then people will like you.
9) If you're going to "cold approach" random girls, go to a coffee shop, or sandwich shop, or bookstore. Presuming this is after you have your muscles, slick clothes, and "peacocking" down, just talk to a cute, nerdy-looking girl who's reading. If you already have the "alpha" persona down, then all you have to do is just be nice, be genuine, and act like you really care. If you have big muscles and act all nice and sweet, she will go BONKERS. Remember, girls at bookstores aren't like girls at sorority parties and clubs, so DON'T be douchey. The muscles will let her know who you are, so just act nice.
10) I don't recommend this for everyone, but MAYBE buy a lapdance from a stripper if you are still a virgin or have erotophobia issues. Get used to touching a woman's body so when the moment comes, you won't freak out. ONLY do this if you feel comfortable though, you don't have to. Decide if it's right for you.
But overall buddy, remember to PUT YOURSELF first. Don't let anyone walk on you. But you have to be nice around girls. But be a tough guy in your day to day routine. Girls like guys who are tough guys out in the world, but are sweet and sensitive when you come home to them.