I'm not going to write about why girls are attracted to certain types of guys and how that relates to our evolutionary biology. But an interesting book on the topic is Sex at Dawn by Christopher Ryan.
I am instead going to write about how predators adapt to their situation and how that relates to guys picking up girls.
For example, there are a variety of big cat predators. The lion and the tiger the most obvious. But the way they look and move are as much a result of genetics as they are a result of their surroundings. One lives in the open plains of Africa, the other in the jungles of Asia. One preys on gazelles and zebras, the other on antelope and elephants. Different needs resulted in different methods and structures to ensure the same thing - survival of the species.
In relation to getting girls, guys in different situations develop different methods towards achieving the same ends - regular sex.
For example, a friend of mine used to work as a cashier at a retail giant. Every shift, he'd have a line of girls waiting to flirt with him. Well, pay for the products they wanted. But because he didn't give a shit about his job or the pay, the fringe benefits were what kept him around. At the end of every shift, he'd have 2-3 numbers and 1-2 dates at the end of every week. He got them by flirting with every reasonably attractive female customer. Sometimes he'd talk about their purchases, sometimes by trying to get them to buy something else. And sometimes simply by blurting it out. He didn't have a lot of time to get to know a person, so he had to keep it short and snappy. Despite being an introvert, on the clock, he was outgoing and friendly. No customer complaints in either department.
Another friend of mine works 60-70hrs a week. He doesn't have time to meet girls except for when he's driving. He has even less time than the friend above. When he sees a cute girl in the car beside him, he doesn't waste any time. The window comes down and he asks if she's single. Regardless of her answer, he then asks for her number. Some girls dig his car. It's nothing special. But it's well taken care of. Some girls dig his confidence and cut to the chase attitude. Some girls think he's cute. And some think he's hilarious simply because he's so playful about it.
Frat boys tend to "hook up" with sorority girls. CEOs and political leaders tend to be married and/or use escorts or interns. Different circumstances breed different methods. In other words, your lifestyle affects who you get and how you get them.
Some lifestyles are better suited to monogamy. Some, despite the best intentions of those involved, tend to be better suited to more promiscuous sex.
And even within those confines, who they sleep with and how they end up sleeping with them vary even more.
I believe in being direct and cutting to the chase because it worked for me and my lifestyle. I am in a monogamous relationship now because it currently works best for me.
Your goal is to find what works for you. If you are in college, hooking up rather than dating is probably better suited to you. But that assumes you're in places convenient to hooking up. Maybe traditionally dating better suits your lifestyle despite being in a situation that encourages other manners of procreation, such as being indirect or playing it slow and smooth.
There is no one size fits all method. But if you find a method you are able to use confidently and consistently, it will eliminate the bad prospects (most likely in the form of them rejecting you) and attract those who dig that about you.
In other words, no matter what method you use, rejection happens. It's a necessary part of the process. And seeking to avoid rejection is seeking to avoid any method and likely to result in no success.