-never say i miss you (less your in a LTR-long term relationship)
-if you got plans and wanna know if shes following up, only text/call once! more than that can make you appear real needy.
-dont call her or text her if she doesnt reply to your previous text. again it can make you appear needy. trust me on this. girls are always busy anyways.
I would go about saving things this way:
you:"hey trouble. what you up too?"
her: "hey. nm. u?
you:"haha nm. you wont believe what happend to me today. lets just say it involved work, vodka, mall and a penguin. haha. anywho. what u doin this week. i might have a few hours to spare:) [here your pretty much making it so you can hangout with her, without asking her. she'll then tell you when you both can]
her: haha i gotta hear this. im free around blah blah though
you: awesome. we'll do lunch/movie/whatev. ill pick you up round (time) wear somethin cute.
her

)
it might not work perfectly like this, but hey, this has worked for me in the past. let us know how it goes dude!
-kryptonic