You, the reader, are probably a guy, and you are probably interested in dating girls, who are probably girls. At the risk of generalization, this feature will deal with ways that guys can attract and hold onto girls, using facts that come from scientists.
Science Fact: Even a brush on the arm is enough to make someone more attracted to you.
Explanation: Nothing is more terrible and perilous than those very first few dating situations where you, as the dude, feel obligated to make some kind of physical move. Should you just yawn and stretch and put your arm around her? But girls have so many body parts. What if you miss and put your arm around the wrong one? What if you successfully make shoulder contact, but it's right at the point in the movie where the shark bursts out of the closet, wielding a knife? Then all you'll get for your trouble is a distressed shriek and an elbow to the nose, which is exactly what you would've gotten if you had just grabbed her lustily and shouted "HONK HONK." Dating is just the worst.
Of course, this all gets easier, and it will soon come more naturally. But for now, take comfort in the fact that any physical contact will get the job done (assuming you're not just going "THINK FAST" and jabbing her in the eyeball).
The Science: Touch has a long and well-documented history of tricking our brains into liking people more. One study had a bunch of students work on problem-solving tasks, along with an assistant who was posing as a student. If the assistant touched the students even briefly, they later rated that assistant as more attractive (and more likable, and more credible). Contact stimulates the release of a kind of brain goop that is also closely tied with lasting romantic attachment. We know this because prairie voles have a lot of it, and they are so monogamous that they practically get married in tiny little rodent wedding ceremonies.
But it doesn't end there. If you're dating someone to whom you are also trying to sell your car, it might help to know that touch makes people more likely to buy cars. It also makes people more likely to do basically everything else; people you touch are more likely to do stuff for you and more likely to give you a free bus ride. But before you conclude that you should just run around groping humans until you get everything you get everything you want, keep in mind that this sort of thing only works when it's subtle.
So What Should I Do About It?
We're talking about slight, casual, unobtrusive touching here. People will tip a waitress more if she touches them briefly on the hand, but they'll tip less than that if she lets her hand linger on their shoulder (and probably even less if she grabs them by both shoulders and shakes them until tip money flies out of their pockets). And it doesn't just have to be unobtrusive, it has to be suited to the context, because presumably you're not going to touch your date the same way you would touch a bus driver.
The takeaway point here is that touch can benefit every stage of a relationship, if you use it appropriately. A girlfriend might feel like your relationship is healthier if you have more social physical contact with her. A potential date might switch from potential to actual if you briefly touch her shoulder while you ask. Just don't walk up to a girl you barely know and start poking stuff at random, or violently grab her face to accentuate that it is pretty, because the only interest these tactics will arouse is the interest of the police department.
Do you touch girls when you're flirting?