While I'm not voting for either candidate this time around, it really makes sense to me as to why so many people would vote for him.
First, I'm going to start by saying that few people like Trump. There are plenty of people who think Trump is really just the worst who still are voting for him. The reason is actually pretty simple. Think about it this way, for example: Trump and Hillary are complete opposites, right? Well, yes, and no. When it comes to economic issues, Trump and Hillary are about as similar as night and day. Trump supports small, individual businesses and decreasing the wealth of the 1%. He's very anti-establishment, doesn't like big banks or Wallstreet, and is in favor of raising minimum wage. Hillary, however, supports big business, and couldn't really care less abut the current gap between the rich and, well, literally everyone else. She's really big into the establishment, and is practically the slave of big bankers and Wallstreet.
On the other spectrum, Trump is kind of a jerkoff. He's not very sensitive or politically correct, and says a lot of bologna that he knows that, a, he can't actually do, and b, he doesn't actually mean. He's racist, sexist, and crude--however, he's honest, and has upheld the same policies and beliefs for a long time. On the other hand, Hillary is very politically correct, but she doesn't really believe a whole lot of what she says. She only has one issue where she hasn't flip-flopped her opinion in the last three years--and that's women's rights.
Now, let's look even deeper. Trump doesn't hate gay people. Or transgender people. Or abortions. In fact, he's really just said, "hell, let 'em do what they want." Bottom line, he's no real threat to our current social issues. There won't be any progression, but we don't have to fear mass regression in civil rights like everyone says we do. Being honest, it's just all a bunch of fear-mongering. Hillary may promise to push civil rights and social issues, but she doesn't actually support gay marriage and I think she could care less about transgender rights right now.
So this is what it comes down to. When someone looks at these two candidates, they have to choose what is most important to them--economic issues, or social ones? If you're a young American in college who can barely pay rent and feed yourself, you'll probably say that right now, the last thing you want is someone who is another slave of the establishment in the white house. If you're lower middle class, you'll probably look at Hillary and feel a little twinge of loathing. If you're an older individual, social issues are probably more important to you. If you're a middle-aged woman, you'll probably vote for Hillary.
Unfortunately, more people dislike Hillary than like her--when it comes down to it, she's not going to win the election because she and her husband have left a bad taste in the mouths of both democrats and republicans alike.
The truth is that some people want change--even if it's in the form of an egotistical, racist little gnome with a spray tan.
I hoped this helps you understand a little.