Understanding the basics of dating is very simple and there are basic fundamentals that trump the concepts listed here:

1) Online dating is BS and totally detached from reality. It's a cesspool, wade in it at your own risk. Your experience and success rate in person will be TOTALLY different from in real life - they are totally unrelated to each other. But sadly, online dating is an important part of dating

2) For the most part, people are either physically attracted to you or they're not, and there isn't much you can do to change that. And a lot of people will only date those who are VERY good looking or match a certain look. Of course such people won't admit it, even to themselves. And furthermore, they complain how men or women are shitty in relationships, without realizing that this is because they themselves are making bad choices, and not admitting that they are the source of the problem (i.e. twisting their perception of somebody who is VERY attractive to meet what they want them to be). And #1 makes this worse because online dating significantly promotes the focus on looks for obvious reasons.

Once you deal with the two items above, the rest of the advice in this article becomes relevant.