Weekends are best for picking up girls in night clubs. However, you need to arrive early before everyone has a date for the night.
If you are in a line, waiting to get inside, see if someone catches your eye, try talking to her and who knows by the time you both get inside you won’t have to look for anyone else.
Once inside the club, look around. Don't be hasty and approach the first girl you find attractive. You want to settle in, soak the atmosphere and scout.
Once you have a girl in your sights, walk up to her and ask permission to join her. Don't just assume she is alone and interested, she may be waiting for someone else or may already be with someone at the club.
If she does allow you to sit with her, offer her a drink. Be polite and friendly, but not assertive. You may need to initiate the conversation, but take a backseat and let her talk if she wants to. The more you listen and respond, the more she will appreciate you.
Once you are done with the first round of drinks, ask her if she would like more. Don't be pushy though - girls like guys who respect their choice and give them room to make their own decisions.
Once you guys are done chatting, assess the situation. If she seems really into you, you can continue the conversation on the dance floor or ask her for a game of pool. However, if you think she is just being polite with her company, take a bow and let her enjoy the rest of the night on her own.
If you guys hit it off and end up playing pool or dancing together, don't automatically assume she is totally into you. Remain polite and respectful as the two of you have a good time.
After a couple of hours, you can ask her if she wants to grab a bite. The two of you can leave the club and get some food. Ask her what she would like - depending on her choice, you can either take her for dinner or a fast-food drive through.
After dinner, you will need to make the call. Depending on the situation, your own liking and her responses through out the night, you can either invite her over to your place for coffee or offer to drop her off home.