I'm curious of what were your experience? And any tips for beginners about to club and what not to do?

Just have fun and drink, dance, whatever. Nothing special about clubbing.

Is it a good idea to pick up chicks in clubs?

That is what 99% of people there are hoping to do. Pick up someone of the opposite sex.

How much do you pay?

Depends on where you live. If in a big city, it could be a $5-$20 cover charge and drinks could be anywhere from $5-10 for a beer as well. Typically clubbing places are more spendy, but depends on where you live.

Do you take someone with you and what do you do if someone flirts with your girl while your taking a leak?

Trust your lady. If some rando flirting with her makes her fall for him, then you're better off without her. 

What can a beginner expect/should or shouldn't do when clubbing?

Don't sit in the corner like you're at a middle school dance. Interact, dance, have fun. That is why you are there.

You will want to go dancing, since that's the only thing to do there. The music is so loud you can't have any conversations, the drinks are expensive as fuck, it's like you try to order a beer and they'll want one of your kidneys in exchange. The girls are not interested in being picked up at all (and who could blame them when there is always a threat of knockout drops and similar horror stories), they only want to dance by themselves. There are tons of drooling men trying to desperately hit on the girls with zero success, yet the men won't understand getting rejected, claim she must be on her period and just go to the next girl. You will see lots of hot chicks with noses high up in the air, and you will witness awkward flirting attempts, maybe a fist fight or two because hey man, how could I know that she had a boyfriend, man? I was just dancing yo and she was shaking that ass and I was like yo, you're mine now, man, I didn't anything bad, okay? Just chill now, alright?!

If you don't like dancing, well then, Just enjoy the music, that's it.

Then, later. As the hours go by the crowd gets sparse. Late at night, four or five a.m., most clubbers will have left. Only the most desparate and/or drunk will stay, the left-overs! Looking at each other through their blurry and tired eyes, stomachs full of fancy drinks and gallons of beer and booze, almost falling off their chairs, and the marbles in their head will bump at each other in unexpected ways. They will realize that this is the final chance, this is it now. All or nothing! And then they will rise, clumsily standing up, stumble towards each other, grunting something totally incomprehensible, laughing about absolutely nothing then falling into each others open arms and sticking the tongue into their mouths. This unromantic and unappetizing experience is actually the true reason why somebody would want to go clubbing. Scored!

Otherwise, just enjoy yourself there, have fun and don't mind if your dancing skills are awkward, that's okay. All eyes on you! Give it all you've got!

You will want to go dancing, since that's the only thing to do there. The music is so loud you can't have any conversations, the drinks are expensive as fuck, it's like you try to order a beer and they'll want one of your kidneys in exchange. The girls are not interested in being picked up at all (and who could blame them when there is always a threat of knockout drops and similar horror stories), they only want to dance by themselves. There are tons of drooling men trying to desperately hit on the girls with zero success, yet the men won't understand getting rejected, claim she must be on her period and just go to the next girl. You will see lots of hot chicks with noses high up in the air, and you will witness awkward flirting attempts, maybe a fist fight or two because hey man, how could I know that she had a boyfriend, man? I was just dancing yo and she was shaking that ass and I was like yo, you're mine now, man, I didn't anything bad, okay? Just chill now, alright?!

If you don't like dancing, well then, Just enjoy the music, that's it.

Then, later. As the hours go by the crowd gets sparse. Late at night, four or five a.m., most clubbers will have left. Only the most desparate and/or drunk will stay, the left-overs! Looking at each other through their blurry and tired eyes, stomachs full of fancy drinks and gallons of beer and booze, almost falling off their chairs, and the marbles in their head will bump at each other in unexpected ways. They will realize that this is the final chance, this is it now. All or nothing! And then they will rise, clumsily standing up, stumble towards each other, grunting something totally incomprehensible, laughing about absolutely nothing then falling into each others open arms and sticking the tongue into their mouths. This unromantic and unappetizing experience is actually the true reason why somebody would want to go clubbing. Scored!

Otherwise, just enjoy yourself there, have fun and don't mind if your dancing skills are awkward, that's okay. All eyes on you! Give it all you've got!