Situational advice girl at grocery

Is she working at Walmart? That's what I am imagining here anyway. Perhaps she is avoiding eye contact because she is embarrassed to work a shit job.

Couple thoughts to be helpful.

1. Sorry, but you sound kind of like a pussy. Avoiding her sometimes, being afraid of an audience and assuming they are cockblockers. You need to be irrationally confident like those aren't even humans around you. If you are ever wondering how assertive you should be, ALWAYS err on the side of being too bold. No one remembers the shy guy that looked away when she actually looked at you.
2. Don't compliment her directly. It's too "try hard" and creeeeeepy. Plus you are probably throwing mixed signals too. If she remembers you at all, which is unlikely at this point since you sound unremarkable by your failed attempts to engage her, you have both approached and avoided her.
3. I'd recommend calling her over to your walmart self checkout thing and claim there's an issue with your item wringing up wrong. Make it obvious you did it to get her attention. Like when buying a soda that's $1.99, tell her it is coming up wrong and insist that the price is $2.50 on the shelf. When she calls you out for being silly to try to get a higher price, she will laugh and you can laugh. Then blame her because she is so distracting you can't think properly around her and threaten if she doesn't tone it down you may need to go to another store. Offer to let her make it up to you and then "pounce??" I think was your word...
4. Never ask. Asking her to go out with you is a beta move in my book. Have some plans in mind and TELL HER you are going to bring her with you. Say like it's a done deal. The only thing you should be asking her is what time to pick her up. Avoid her having to make a yes/no decision as women tend to say NO to any question or decision. Giving her a choice between 7pm or 8pm or Fri vs Sat.
5. If she says no, it doesn't mean anything. First rule in asking for anything is you may need to take 7 no's to get to a yes. She may have feelings for someone, a boyfriend, may be embarrassed at work, or just wants to play hard to get. Let her know it's her loss in an outcome independent tone. "Hey, it's your loss, it's going to be a great time" with a smile and laugh "I'll let you know how it went when I see you again" kind of reply and when you see her in 2 or 3 more visits, try again. Keep up the image that you have tons of pussy at your disposal and are completely un-phased that she can't come this time.