I'm fairly new to the whole dog/pitbull owning thing (my pup is 5.5 months and I got her when she was 2 months), but one thing I've had a lot of success with in making her obedient is not just having her sit for things (water, food, leash, outside, inside, treats, whatever) but I make her "wait" before a lot of things until I am satisfied. A great example is when I wake up in the morning to let her out of her crate and start our day, I'll make her "sit" in her crate, then I start saying wait and open the door. If she moves at all, door closes again. As she's waiting, I'll walk away a little and then repeat the command, then rinse and repeat until I'm almost completely out of the room and she's still sitting there waiting and you can tell she wants to get out SO BAD. Then I finally say "OK" and she comes running out to give me a kiss. I do this every time I give her water and every time I feed her to lether know that not only does she need to perform an action (sitting), but that I am unquestionably in control of everything that she wants. Once I started doing that consistently at about 4 months until now, her level of obedience has completely skyrocketed to the point where I'm able to modify her behavior on a wide range of things fairly easily (leash pulling, jumping, coming when called).
Just thought I'd throw that out there as it seems like a simple thing to add to the routine you've already got and has made a huge difference for me.