Night game is much more difficult. the fact that she's gone out IN ORDER TO get laid paradoxically makes things more difficult for you, as her "process" if you like centres around aggressive use of the bitch shield, and screening of weak males, drunks, and general dickheads. The other thing, probably even bigger of a factor than the bitch shield, is that she's with friends.
For a girl, getting sex involves a severe tension between desire and reputation-consciousness. If she can have sex with David Beckham then it is no problem, she desires him and her reputation will be enhanced by everyone knowing she was with him. In the more likely case the reputation aspect is at best a question-mark, so she may be highly desirous of fucking you, but it will also depend severely on what her friends' attitude is to the deal.
Just the presence of her friends may be enough to make her decide that although she likes you, she does not like you ENOUGH to take a risk. Or if the friends are negative on you (particularly), or negative on her getting laid (generally) then that also spells trouble for you.
Pairs of girls can be pretty good, especially if they're besties and non-judgemental of each other. But in that case it's rather good to have a wing so that you can pull them both to one of your places together, or at least occupy the friend while you chat up your girl.
In daygame, none of these factors apply. She doesn't have her bitch shield up, totally the opposite. She isn't expecting to be hit on at all, and she's highly open to chatting with those encountered in the course of her day (the same way as you are too, unless you are busy or preoccupied). And if you open with a genuine interest or direct opener, then she knows she is being hit on, but the surprise and intrigue factor is generally enough to get your foot in the door so to speak.
She also usually isn't in a group. When thoroughly warmed up I do approach groups and sometimes enjoy a bit of banter, though usually not much comes of it. And occasionally I will approach something like a mother/daughter pair, even more occasionally the mother will be highly approving of us making a date (but I'm a bit reticent about going for this given I'm 43, if I liked the mother I would go for it, haha).
The best way in daygame is simply to approach a girl who is going about her daily routine, which might involve things like grocery shopping, or perhaps she is on her way somewhere or perhaps she is waiting for a friend (if so, you need to suss this out, and chat her up a bit and discreetly get the number before the friend arrives, then make no reference to the fact that you have her number once the friend is there).
If you do it like this, then it's highly possible her routine will be flexible enough to go for an insta-date, or at the very least she will have time for say a 10-minute conversation in which you build enough intrigue to get her to agree to a date. I've also often had it happen that they couldn't stop, but they quickly agreed to the date anyway, this indicates perhaps that there is little male action going on in their life.
That's not to say that daygame is the only game in town. Nightgame is totally fun too, because of the different challenges it brings. Online also, has different challenges and potentially can allow you to build a process to get you tons of lays very efficiently. You could certainly develop a preference for either daygame, nightgame or online depending on many factors both internal to you (personal preference; your specialized skills; what challenges you; etc) and external (efficiency considerations; logistics; your job; etc).
But daygame is highly efficient for the reasons stated above, and in my opinion is also a great learning vehicle. The fact that you have the balls to approach a girl in the street and make your interest known, is great for you (it helps you to develop a healthy attitude, a skepticism towards society's norms, and a feeling of abundance which you don't necessarily get in nightgame or online), and helps her to give you a lot of chances if you do fuck up in various ways.
cheers, Ray