@bigdave17 is like the teenage brother who's just getting his feet wet in the dating realm. This is not a mathematical problem you can solve with your brain. In fact, you do not have to think on this, just do.
1) Go to the bar.
2) Get a drink (get ginger ale or something with no alcohol if you cannot control yourself when you're buzzed)
3) Walk over to some groups of people and chime in.
4) After a few minutes, go to the next one.
5) Rinse repeat.
6) You see a lady in the corner of your eye looking at you, then looking right away, go and approach. Walk over and chat. What are you drinking. Look at her shoes, say, love the shoes. I can see you have a sense of style. I like that in a lady. Pro tip - have nice looking shoes. After that, just expand. Stay for a few minutes, and then say well, I just wanted to introduce myself, and I going to chat with a few friends over there. IF you are interested, say to her, let's chat again before you leave. If she hangs around or approaches you again, you're in. Get the number and call her 3 - 4 days later, not next morning. If she's in her 20's, text would be better.
YOU: Hey!!! it's Big Dave from the other night at the Roxberry
Her: Oh hey!!!!
YOU: Listen, I'd love to meet up for some drinks this week. What day works for you?
HER: Kewl. I'm free Monday.
YOU: Let's meet at Joe's Bar at 7pm.
HER: Gr8!!
YOU: Anything changes let me know.
HER: U2
Simple and to the point. DON'T TEXT HER AGAIN!