I like to answer questions on Yahoo! Answers, and I see this one a lot. I'm going to take a crack at answering it from the man's point of view. It is, after all, a guy the girl is trying to attract, so asking the question of another girl is missing some important insights.
I've come to realize that there are three people in any successful relationship. There's you, there's your partner, and there's the composite personality between the two of you: "us." "Us" is the single most important part of the successful relationship. If there's no "Us," there's no relationship.
"Us" is the embodiment of the love and security between the two people. There are many ways to define "love" in this context and I'm not even going to try to address them. But security is the ability to rely on your partner to provide support, be emotionally accessible, and not represent a threat. How you define "threat" is up to you, but if you consider your partner a threat in any sense of the word at any time, then something's not quite right.
So: how to find the "Us." Let's look at these three subject headings: support, emotional accessibility, and for want of a better term, compatibility. I say compatibility because the term "threat" covers quite a lot of ground beyond the obvious physical connotations, and compatibility brings in a bit more while leaving some of the less relevant bits of "threat" out. We'll get to that.
Does he support you? I'm not talking about the lowest common denominator of financial support, picking up his share of the bills and the rent, that's low-grade stuff. Does he support you. Is he aware of when you're having an off day and try to make it better? Whether or not what he's doing is successful is beside the point. Women and men communicate in completely different languages and he's going to get it wrong from time to time. If the guy is attentive to your needs and taking them into account when decisions get made, there's an "Us" there whose well-being he's trying to protect. You matter. That's a really good sign. If, on the other hand, he's reluctant to even pony up for the rent, then you have a serious problem. Your partner isn't willing to offer support for anything that isn't completely his in the first place.
Emotional accessibility is a woolier subject. It's the other side of the coin of supporting you, it's making himself available for you to support him back. If you find you're the one doing all the talking at the end of a busy day, and his pat answer is "fine" or worse, "same as yesterday" when you ask him how he's doing, he's not willing to let down his guard to let you become more of his life. Popular sexologist Susie Bright memorably said, "It's nothing to tell what you don't like about something. It's much more revealing, says so much more about you, to say what you do like." So if the only opinions he offers are negative ones and his most positive statements are in fact neutral, you haven't been invited into the sanctum sanctorum. You are still being presented only with your partner's public face.
Compatibility is the simplest factor to consider, though it covers the widest range of individual traits. If you really like a lot of bedroom calisthenics and he doesn't then that's one point of contention. Maybe you like to stay home and he likes to go out. These are the obvious, external things, behavioral things. There's also the internal stuff - maybe he provides the support you need but you'd rather he didn't. Many people prefer not to have their independence challenged. It's not always clear what someone might take as having their toes stepped on.
So this brings us to the ultimate point: How do you make him love you? This is the part that you really don't want to hear.
Keep reading! You can make him love you but the more important question is, why would you? To make that happen you have to change your own behaviors to better suit his natural state, and you can endeavor to change his behaviors to suit your natural state, but that places both of you under uncomfortable, unnatural stress. Unless something happens to make your personality/-ies shift to this new state and take it on as a natural state, you're going to chafe at each other until one or both of you realizes that the relationship is the source of the stress. Once that realization is made, it's over.
And there you are. If you're trying to make someone love you, you're really the only one in the relationship. Your partner is in it for funsies, not for keeps. In my experience as a man, there's strong sexual attraction that feels like the base of a relationship but is really just hormones, and there's friendship. To have a good friend that turns out to make a good mate is the base of a strong relationship. It worked for me.