Ok here's a 101 on going to a bar:
First go with a friend, alot easier then going alone, ask any/all your friends if they want to go out to the bar on the weekend. I doubt all of them are gonna say "no". Going in groups are alot more fun so even 3 or more people the better.
You can even hangout at someones house first, drink, play games whatever.
I donno what time the bars stay open there, but here its 2:00am so arriving at midnight or a bit before is a good choice, the bar will have lots of people by then and people are starting to get drunk and the music is better.
Try to find a bar to your music tastes, so if your not having fun the music will be good...
try to find a club with alot of poeple in it, especially if your going in alone... more people the better, more people to meet and if your going alone its better so its not just you sitting alone with 12 other people together at one table lol
dress good but don't over do it.
when you arrive there might be a line-up just get inline, if not go in.. you might be carded so bring some ID. Quite simple they ask for it, you hand it over, they look at it, they give it back and you go in.
If its winter and a pretty big club they will have a coat check, just hand in your coat and you will get a ticket to get your coat back when you leave.
when you enter its gonna be dark, people danceing in an area, some tables, flashy lights, loud music and a bar or a couple bars.
so go right upto the bar and get yourself a drink, if you don't drink get a coke or something. But even if you don't drink try and get a drink anyway, if you don't like the taste try and fine a drink that you would. Theres 1000's of drinks out there, say if you like orange juice, get a screwdriver (orange juice and vodka) or coke get a rum and coke. if you really don't like the taste vodka is your best bet cause theres less taste to it. Drinking makes the experience ALOT better just try it out and buy 2 drinks and see how it goes.
when your at the bar get your money out place it in your hands so the bartender can see it (have it in your hand in good view and place it on the bar when your next in line and they will notice after a bit and come over) tell them what you want... if your want 2 beers don't say "I want 2 beers please" ask for 2 buds or a blue or whatever beer yous have in the usa. they will come back with the drinks, you hand the money, they will come back with change. this is where you leave a tip... the more drinks the bigger the tip. They will always come back with change like 2 quarters, so take the money and leave 50cents or a dollar on the table and walk away.
now wait for your friends to buy there drinks and look around and find a table to sit at, or you could stand near the dance floor (there will be other people standing there too watching) and watch people/the ladies dance.
now if you go after midnight people are already buzzing and are generally more friendly so don't be afraid to start a conversation with anyone, you'll find people will start usually small conversations talk a bit and move on.
last call means its your last chance to buy a drink.
Don't like the bar your at? leave and goto a different one till you find one to your tastes, different bars have different music and different crowds of people. Of coarse in bigger citys the more selection you will have and you will have an easier time finding one...
hope I helped out somewhat...