1st of all, get her out alone with you, if this is impossible and she keeps flaking you, then forget about her
2nd of all, test compliance and go for a kiss, don't know how?
chiefs-guide-to-outer-game-vt75887.html
^ this is a more detailed guide to what I am suggesting, but it can be simplified as this
when you meet her, give her a hug and a kiss on the cheek, tell her it's been so long, if she dis-allows this, then she is non compliant, if she is fine with this, good sign
now, if she is compliant, next thing you do is isolate her somewhere that you can get close to her and put your arm around her, talk for a bit with your arm around her, if she is comfortable with this... all good, go for a kiss, there is no right time, just do it when you want to
keep it short and sweet, no tounge, look into her eyes and look at her lips, go in slow, save making out for her for a more private place where you can have sex with her
now, if she complies with that, invite her back to a place where you can have sex, give her a reason to go there besides sex, like, poker, or a movie, or a drink, or to check out that cool song/video that you want to show her and she just has to see, as long as she is older then 16 and not a retard, she knows the deal (even if she pretends otherwise to maintain her non-slutty image)
if she comes back to your place, sit her down, kiss her again sooner rather then later, start making out with her, start lightly moving your hands over her body, start getting more and more gropy and sexual with where you are touching gradually and as you make out with her, start removing pieces of your clothing one at a time, give her time to heat up so she is nice and wet, after a good 10-15 minutes of making out, start playing with her ass, move the cheeks around, if she's all good with that, just start rubbing her puss, she's all good with that?, then finger her, she's all good with that? then tell her to ''bend over, I wanna see'', or say ''hey just put your face down and your ass up, I wanna see'' if she complies with that, put your penis inside her and start pumping, or you could use the whole mystery method thing and say, ''do you want me inside of you?'', either way it doesn't really matter, if you can finger bang her the chances of you not getting laid are pretty slim
and for trouble shooting look up posts that handle topics related to LMR
if you can't reach compliance with a kiss, she is not interested in you, cut your losses and move on to a different girl, if you can reach compliance for a kiss but she starts flaking on you in a repetative pattern, move on to a different girl and forget her, if she flakes to begin with, forget about her and move on to a different girl
GOOD LUCK