When you're making out with her, start kiss her on the neck. Then slowly start kissing her lower and lower down her neck until you reach her breast area. If she's moaning this means she's really turned on and you can probably start fingering her, but don't rush into her pants yet. Rub her pvssy over whatever she's wearing, and if she's fine with it, put your hand in her pants over her panties, start rubbing there too. Don't forget to stop kissing her. I've also found it that girls like it when you nibble on their ear and talk dirty to them up close. I say stuff like "Oh man I want to put my finger in here so bad, but I don't know if you want that..." and at this stage they usually don't deny it, they'll tell me they'll want it or sometimes they even take their pants off themselves and remove their panties!
After that it's usually smooth sailing; if you don't fvck up you should be inside her vagina real soon but don't forget to use dirty talk and don't forget to stop kissing, those are the two things that are really the source for escalating. Remember that women like their whole bodies to be embraced, not just their vaginas.