How to show that you like someone without going OTT

My friend is having a problem with a guy that obviously likes her but won't say anything. He is very very obvious when he's around/speaking to her and pretty much everyone that knows them knows that he  likes her.
My friend also knows, and we were saying that he needs to be more subtle and less stalker-ish when trying to get girls.

So, I'm going to try and get some pointers for people: How to show a girl you like them without going OTT (or being a stalker :P)

1. TALK TO HER. But dont drop everything/every other conversation just to say hi, it's seen as weird and it's just obvious. 
2. REMEMBER THINGS. Remember little details about her, maybe ask her about them. It'll make her feel and show her that you care about what she has to say, even if it seems unimportant.
3. DON'T LIKE EVERYTHING ON HER FACEBOOK. That's just being a stalker.
4. DON'T AGREE WITH EVERYTHING SHE HAS TO SAY. Take interest in her opinions and views, but girls like a guy with backbone that they can actually talk to and debate with, agreeing to everything she says will get boring and she will lose interest amazingly quickly.
5. TREAT HER LIKE EVERYONE ELSE UNTIL YOU KNOW SHE LIKES YOU TOO. Acting like she's the only thing that matters might seem sweet to you, but it can be incredibly awkward for her, especially if she doesnt feel the same way. Get her as your friend first by ACTING as a friend, then see how it goes from there.
6. FIND SOMETHING YOU HAVE IN COMMON. You're instantly more attractive if you have the same interests as her/like the same programme/film, but don't fake it because you'll look like an idiot if you try and talk about it, then realise you have no idea what you're talking about. 
7. DON'T BE CLINGY. Attention is always great, but don't overdo it, being too OTT will put her off you, give her space!

Hopefully if you're having a problem with this particular dilemma then this will help! If you have any more suggestions then don't hesitate to add them in a comment below! 

Obviously this can be used for girls on guys as well, or anyone for that matter, just DON'T BE OTT.

I hope you guys liked this and found it helpful/entertaining, DFTBA guys xx