When you go out at night
-don't be outcome dependent ("are there gonna be girls there?"). it shouldn't matter because you're there to have a good time, girls are secondary and optional. there's nothing more attractive than having fun.
-don't scout. don't look around the room checking out all the girls. walk into a bar, find the nearest empty chair, put your coat on it and order your drinks. girls check out guys too and they find scouting lame and sometimes creepy.
-if you make eye contact with a girl maintain it, never be the first to break. alternate between focusing on each eye to make yourself more comfortable. if she looks away quickly and never looks back she's probably not interested. if she looks away then keeps glancing back she might be interested but shy. if she looks down she might be interested (down could be a sign of submission). if she locks with you she's probably interested.
-don't job interview ("where are you from", "what do you do", etc). you can ask those questions just not up front, ask them spread out over time after you feel mutual interest. ask opinion questions up front after introducing yourself it makes for easier and better conversation.
-wear your clothes, don't let them wear you.
I am by no means an expert on girls or even close, actually I'm a total noob. But I have been doing these things lately and have notices far more attraction and better results. These tips will help you.