To be honest, what makes me click on a story is more of a list of things that aren't there, rather than things that are:
1) No 'commercial spokesperson' talk, like "Are you looking for action? Adventure? Laughs galore?? Well, come on over to [insert comic/novel] and" blah blah blah.
It irks me...partly because it's corny to the point of transparency, and partly because...well, most of the writers I've run into who do things like that have a * certain * sense of humor that does nothing for me.
2) No self-deprecating talk. I've had bad experiences with people who are always insulting themselves, and frankly I don't trust them.
3) No 'cute' talk, like "please read my story ^w^!!! If you would click on this link it would make me super happy<3anyway have a nice day!!!1!"
...This is just a matter of personal taste.
4) No comparisons to existing media. I understand the value in doing this, and I used to do it myself, but honestly when I see it I just think "Oh, so this is gonna be like [thing], but slightly less interesting" and I don't feel motivated to look into it.
5) No carbon-copies of stereotypical manga synopses. Like, if you're going to write BL love story #320403, at least don't do the thing where you go "A is in love with B...but A doesn't know that B is a prince in disguise! When B's secret comes out, watch the chaos unfold!"
...Again, personal taste. But additionally it just reeks of unoriginality. I look at it and get the feeling that the entire story will just be a big collection of tropey manga lines and situations that I've already seen before, with no additional depth.
In my experience, the above strategies are so common, that anyone who doesn't use them automatically piques my interest.