1. Read up on push/pull a little if you can. You want to kino to get her used to your touch, but you also want it to be apparent that you're not physically available to her at just ANY TIME she wants. Balancing attainability is key here, and was something that was one of the more difficult things (for me, at least) to learn when I first started out. An example here is to lean closer to her as if you were going to kiss her, then pull back. Keep her guessing!
2. Tease and neg her a little bit. Don't do this too much, though, or you'll come off brash and she'll think you're an arsehole. You want to be smooth too, and don't react much (read, overreact) if she teases you or negs you back.
3. This is one is VERY important. Strong, sexy eye contact. When you're looking at her eye-to-eye, just think about shoving your rock hard dick inside of her. She'll feel your sexual vibe, trust me.
4. Innuendo/Suggestion/etc. You can say things that could be taken one way or another, sexually or not. An example is lets say a girl tells you she has to study for a big test later but is so sleepy and doesnt know if she can stay awake. You could say something like: "Oh yeah? I bet I could keep you up like all night..." and it can be taken sexually, or not. It gets her thinking about the two of you together.
Chase has a great article here on building sexual tension:
https://www.girlschase.com/content/sexu ... -and-randy
Your other question: Sometimes I might gently knock a girl off her stance or bump her and say something along the lines of "Hey young lady, I did NOT come here to get harassed!" or something similarly playful. There are a ton of these, but its best to come up with them yourself- that way it doesn't seem forced or awkward when you do it.
Cheers brother,
NJ