Maybe I'd have had better chances with something a bit more elaborate, but didn't come up with anything in the moment.
If I can butt in.. Lot of girls don't know why you approached them. Some of them are just dumb to think you only wanted to say hi. So, just saying Hi is a low success opener, unless she's already hooked just by your fundamentals. That's only one aspect of it. In order to hook a girl, you need to go beyond an approach.. easiest is cold read or tease or accuse.
You're putting in effort to approach but wasting those approaches without following up. How about you approach for a hook instead for approaching?
In all of your sets, you say you liked something about the girl but you never seem to express that. I read about a couple of sets where you said "girl had great hair" or "great body" etc.. why don't you weave them in your approach instead of just saying hi?
You want her to hook based on what you liked about her and so you're approaching and not cos you wanted to approach. This serves 2 purposes: 1. It'll bring down pressure off of you to approach 2. You'll be congruent with your approach.
For ex: If you saw a red-head, your standard approach for hooking should look something like this:
GB: Hey / excuse me (pause.. until she gets your attention)
She: Hi
GB: Your hair.. damn! It's on fire (say it with passion)
She: Thanks
From what I see, your sets are ending here but you should continue... this is where you get her to hook (I'll give all 3 examples of tease/accuse/cold-read. Choose whatever suits your personality the best and use it)
Tease
GB: never stand near a traffic signal(comparing her red hair to traffic light), you'll cause a lot of accidents.. (with a smirk)
She: hahaha..
(If she still didn't hook and only laughed, you continue)
GB: now whenever I'm at a traffic signal, I think I'll remember your hair..
She: hahaha.. you're funny. What's your name?
Accuse
This is one level higher than tease but you need to be cocky to pull it off but the hook rate is higher compared to a tease
GB: Are you trying to distract guys at the traffic signal to cause accidents? Damn.. you're wicked!
She: Hahaha
GB: you remind me of the red lady from game of thrones.. she was wicked too but I'll forgive her cos she was sexy (notice the push/pull?)
She: you maybe right.. I'm wicked and dangerous ( generally if a girl is hooked, these are the kind of responses she'll give but it can be anything else.. point is, she's hooked)
Cold-read
This is more of a slow paced game relying on fundamentals heavily.. less emotionally charged.. but seducing her only with your eyes while talking something normal.. think of slow boiling a frog
GB: it makes me think you're someone who's very passionate in life
Her: oh.. why do you think so? (Hook)
GB: one for the color itself, cos red is fiery and passionate and secondly someone who dares to be different are generally passionate in life..
I hope next time you go out, you're stepping out your door not to approach but to hook a girl. Good luck dude
BTW, forgot to add.. if you're full of adrenaline and can't come up with follow up statements, have a few pointers in your back pocket.. Like:
Hair= comment on color
Dress= comment about elegance
Shoes= comment about elegance/personality
Bikini= comment on weather/fitness/health
Smile= comment on personality
Eyes= comment on warmth
Good body= comment on fitness/health etc (hope you get the idea)