After several trials and errors, I'm sharing with you my tips on how to approach a girl and how to talk with her, in a direct and natural way without routines, false time constraint and any other wasteful technique.
First, you have to be ready and you should have a manly body language and a good dress style.
[The following method works for me. Of course, sometimes I make use of the Mystery Method].
So, you see a woman you like, sitting with her friend(s). You need to approach them before they see you. That means if you are going to need some time to think about it, do it somewhere else, where they can't see you hesitating or worse, looking at them constantly.
Approach them from their front. Avoid to approach them from any of their side, where they can't see you approaching them because you will get a bad response. Before you get closer to them, smile and look at them in the eyes. With this, they will understand what are you going to do and your smile will calm them.
Go straight to your target and say to her that you like her and want to get to know her (or she looks like an interesting person and you want to say hi).
Introduce yourself with her and immediately ask for her friend(s). You can say something like "Is she your friend?" and introduce yourself with her.
Immediately give a sincere compliment to her friend, you need her by your side. Do this by telling her that she is wearing something nice or she has a sense of fashion, etc. She will like it (especially if she is a woman who does not get a lot of attention by men) and she will like you so she will let you talk to her friend, without block you.
Do not ask the same things in both girls. You should work with your target. If you are asking the same questions to her friends, your target may think that you are a player, or you like her friend or even you don't have something else to say.
If you do it right, she will find you attractive. Your next step is to set a qualifying frame, by asking her some personal questions. Without attraction, girls won't answer personal questions to strangers, so you have to win her first.
The conversation with girls is very easy. To help you, women give you anything you need to start and continue the conversation. You have to listen to what she is saying and choose a few words for further discussion. This makes you look sincere and helps to build a deeper connection with her.
For example, if she talks about her "neighborhood", ask her more about the neighborhood she grew up, if she talks about "dogs", ask her if she has a pet or what pet she likes.
You can build more connection with her if you have some interests. If she likes you, you can say something like "Really? Wait a minute, we have to stop talking because I will fall in love with you. I also enjoy this or that".
Note that you should continue to talk about "this" and "that", in order to take her mind from "I'm falling in love" part and avoid raising the shield a woman have for such things with strangers.
If you build enough rapport, then you can take her number or ask her if she is going to somewhere else. The number you will take will not be a "flake", because you had a genuine connection with her.