Hey guys,
I'm starting to think, maybe my AA is less related to approaching people. Because when I want to (only when the goal is not hitting on a girl) I can approach just fine.
Thing is, when I imagine approaching, I can never imagine the conversation. I honestly wouldn't know what to say (after the opener etc).
It's not that I'm boring, I'm quite a big geek and I usually talk a lot about my geeky hobbies with my friends, but not sure that's right when you're with a girl. When with family and friends, I'm usually very active in the conversation.
So, any suggestions as to what I can do?

Imagine the targets as friends (I prefer never to imagine them as family members because I would never flirt with a family member). An opener is only used to actually start a conversation. Whatever you talk about make sure it SOUNDS interesting. Always associate it with positive words. Another trick would be taking a key word from everything they say and asking about it. This keeps the conversation going longer. Another thing is teasing, always playfully tease them, unless they open up to you about something which happens on occasion.

Well, I was with a few friends a few nights ago.
We were with a few girls, when me and a specific friend started talking about our usually geeky stuff. The 2 other guys that were with us just left to get something to eat, and we were left with the 2 girls, which more or less distanced themselves from us when we talked about our geeky subjects.
Usually when I'm with family, they all listen and everyone is more or less interested in these things and joins the conversation. Maybe it's a matter of maturity, I honestly can't tell yet.
I'm only 18, but when I am with friends if we're not just being guys and doing something stupid, I usually talk about these things. Maybe it's just inappropriate for "my age"?
One of my friends put it like this "If you keep talking about those subjects you'll never get a girl".

Well for one, you should never listen to the advice of a friend unless he's proven himself first. If the subject is interesting to the girl then you can definitely talk about it with her, you just have to look for subtle queues to see if she's bored or not. As long as a girl isn't bored you can definitely say or talk about anything. Just try to make everything you do and say "fun", because that's what girls are after. They don't go out to get guys they go out to have fun, always remember that.