First, know your music it will give you more confidence. Then you need to give yourself the best self image that you can. I have watched lots of live videos from performers that I admire, and am impressed by. Then I try to see and understand why they are so good. Usually it comes down to attention to details. Build your show from the start. Solid set lists with segues, and practice your sets and the show, song to song, to song, with just an idea of what to say during the  breaks (try not to ramble and keep it short). I don't think you need to practice what's said, just have some idea, cause things change from gig to gig.

  Right before I hit the stage, I like to loosen up, and clear my head of any nonsense, like bills, or other jobs,  or relationship problems.  As I like to drink beer.  I will usaully have a few before and during the gig.
  In between sets is meet and greet time. network and promote. We have our own button and key chain  maker we like to give some of these out during the gig. 

  If you know your songs and have a solid self image, the next thing is experience. I can go to almost any jam night in town, and just by watching how they walk on stage, can tell the ones who have been there awhile, and the ones new to the stage.
  Experience: IE Nobster had a nightmare gig. He did not quit just learned from it. All musicians have these even on the biggest stages, and even if they have been playing for years. S#%t happens, after alot of S#%t happens ; you realize not to sweat it. As a bass player I jammed with in Dallas said when things went bad, "Dude it's just Rock-N-Roll".  This always put things in place. Amp blew up, "That's Rock-n-Roll" , two bands booked for the same gig, "That's Rock-n-Roll" ect. Got to drunk fell of the stage "That's Rock-n-Roll".
 
 I'm not usually into performers that talk alot between songs. A little banter with the audience is needed. We usually try to keep it light and fun. Self Deprecating humor among ourselves works well. 

Remember to have fun.
 I look at some audience members, but something I was told by a drama teacher; that if you focus your eyes about 1 foot over the head of the people in the back, it looks like your looking at alot of them (way the eyes are made or something).
  When playing clubs that have servers, always remember to remind the audience to tip the bartenders and servers.

 

  IMHO the best thing you can learn, is to love to, "fly by the seat of your pants".