In before the thread gets locked because of the pretty obvious arguments that a certain user is bound to have generated, I'll just answer my thoughts (as a definite non PUA) on what I read into your initial post. These may go against the typical PUA ethos, but work for me.
Firstly you sound far too desperate, and most women find this a turn off. Always complimenting them on their looks (so much so that eventually she tells you to stop) just makes it sound like you think they are out of your league, or that you are superficial. There's no need to put a woman on a pedestal, as she'll either think you are beneath her, desperate, or a liar (or worse, a PUA). "You are pretty", "You are beautiful", kind of lame and more stuck for things to say than actually saying anything. Show respect for something she can actually affect, like an item of clothing or jewelry (to me, "I like that shirt" is far better than complimenting looks), just don't overdo it and make it casual.
I would also cut out so much of the "can I tag along", as this makes you sound like a poodle. It leads to you sounding weak and desperate, rather than "can I tag along" I would have phrased it to understand if she wanted to meet the next day, as a lot of the time people just don't want to say no to someone else (yes you get to "tag along" but you invited yourself). Why not, "Hey I'm not doing anything
tomorrow, here's my contact details in case you want to go out again"). This puts her in control, but also gives her the option of messaging you in the middle of the night if she's feeling like she wants some company.
The staring also sounds a little creepy, and talking about underwear just seems a little inappropriate as it sounded like she'd tried to tell you that she already had a boyfriend, but you were still pressing for more. To me, the fact she told you she had a boyfriend, and even went as far as showing you pictures to prove it should have been a red flag. Pushing someone into cheating just leaves feelings of guilt afterwards. I would tend to think "Well, if he's happy for me to cheat on my boyfriend, that shows he has no morals, and expecting him to be faithful in return is stupid, especially as I've shown him that I can't be" Also, telling someone, to try and woo tham that her boyfriend is bad is just insulting her choices in life. It's becoming more common in today’s society, especially amongst politicians to show the negatives of the opposition, rather than the positives of themselves, and it's normally because the positives are just not that appealing.
You also seem to be wanting to define this experience as a failure, despite having a few enjoyable days in good company. You can either look at life as "success" and "failure" dependent on whether you get your dick wet or not, or actually look at life based on whether you had an enjoyable time. I know this is completely against some of the PUA strategy, to think of women as human beings, but if you both had a great time (which it sounds like you did) then getting laid happens an awful lot more than the PUA crowd would lead you to believe. Maybe not this time, but I certainly wouldn't call your days a failure.
To me, despite sounding a little too desperate, you seemed to have enjoyed yourself, and she wasn't too put off by it as she's still in contact. I'd avoid going down some of the PUA routes (especially any recomended by 4vibes), maybe listen to some of the well rounded members of the community and just be yourself. You sound like you don't need much tweaking, so no manipulation or mind games to make women like you, you just need to continue being a well-rounded human being that is good company and things will fall into place as you go through life and pick up more experiences.