When asking why you are still single, I would say that it’s best to look at the obstacles you are facing. Some people just can’t find someone because they are looking too hard. Others are looking with the right amount of effort, just the wrong place/venue. Others might have unrealistic expectations, that are put into place with good intentions, but have the flaw of being too high or narrow.
So, what kind of obstacles have you met in romance? Has it been that nobody sees you that way? Is it that the people who you are attracted to shun or ignore you? Are you forever in the “friend zone”? Do you hate the way you look? Maybe you just don’t fit in at the venue you have been looking. Maybe you need to find a place that is more in-line with your interests.
And that’s the best advice I can give.
I would say that the best way to increase your ability to find companionship is to find your niche. Throw yourself into the things you love. Get good at them. Master them. Join clubs focused on them. Get out, do fun things. Just meet people.
Don’t rely on the internet to find someone. I have a profile on a dating site, and yes I get dates from it. But it’s really more of an art than a science, and it took a LOT of trial and error. Getting out among people, and just being yourself is the best way.
It does not matter what body type you are. I have seen women of every body type in happy relationships. My ex was 420lbs, and would get asked out constantly by guys. In contrast, I know a girl who is cute, petite, fit and she can’t seem to get into a relationship. Nobody wants her. So don’t blame your looks, your weight, or your height. For every type of girl, there are guys who are into you.
As far as those activities I mentioned above go, they give you a time and a place to meet others who share your interests. Do it because you are into those things, and not because you want to “meet someone”. Another enthusiast just might take a liking to you.
In the end, it’s how well you’ve filled out, both emotionally and intellectually, that will attract the right people. If you were looking for a quick bang, you could probably put an ad on craigslist, and have a hundred offers by sunset. But you obviously aren’t after that, or you wouldn’t have posted this question.
Be yourself. Be the best, most awesome, dorky, awkward, artistic, nerdy, whatever, version of yourself. When you are solid in that foundation, you will have boys lining up to date you.
And that’s the best advice I can give.