first of all you can't make somebody jealous if a.)they have lots of options or b.) they have low interest level in you. if you are in either one of those two boats with this one you're s.o.l.
now, here's the deal, ususally when a guy suspects somethings going on, he's not just a paranoid bastard, he's right. guys know how guys are and if she's goin out with "friends" that are male all the time that should trigger the "somethings not right" thing in your head cuz in todays society guys cannot be friends with women they are attracted to in a platonic way(women can however) if she's out with them and they are attracted to her you can bet they are at very least makin out.
in some cases there is no solution that can fix the problem with a specific girl, only solutions that fix the dynamic so you don't ever percieve a problem(because you have so many other options). men that have lots of options don't perceive a problem with one girl in particular because they aren't afriad of loss. they don't worry about "is she cheating on me" and stuff. the focus is shifted from her to you(where it should be).
bottom line, you can't make somebody jealous if they aren't really really into you already.
as far as nexting her, nah i wouldn't, just wrap your tool so she doesn't bring you home a surprise and work on expanding your crew to include a few more chicks, the boost in confidence, you may find, will bring her around, and if it doesn't se la vie.
-J