A lot of people start out in your position, with little available to budget or spend. I did, but I got through (only) a week before my next paycheck with austerity but relatively little trouble. You've already gotten that idea, which will make it easier.
Here's what helped me:
1. No discretionary spending, not even so much as a chocolate bar (unless it's medically necessary

). Only enough gas to get by until you get paid. You get the idea.
2. Live out of the pantry and freezer. Buy only necessities: enough gas to get you to your next paycheck, milk and bread, veggies and fruit, and get them at a discount store if you can. Cook meals from scratch. Chili is a favorite good-but-cheap complete meal: brown cheap ground beef and a chopped pepper and onion, and dump in a few cans of generic pinto beans and tomatoes, simmer and top with generic grated cheese and you'll stay nourished.
3. Sell something. Dig in the back of closets and your garage and underprice them to go fast, at least at first, because you need cash
fast. That helped pay immediate expenses, get my budget moving and start rainy day funds for foreseeable lumps in the road. You're going to need as much extra as you can get your hands on for the first few months.
4. Negotiate bill deadlines. Utility and phone companies are almost always willing to arrange late or partial payments. The key is to call and ask politely. Your wireless company may do this too, but I wouldn't count on it. Just remember, you're going to have to pay those bills with your next paycheck.
I hope that helps. You're on exactly the right track, so just stay on it and things will get a lot easier very quickly!
"It’s still all about the method. Fancy Cloud Sync algorithm aside...the software is there to help you become more aware (Rule One), anticipatory (Rule Two), flexible (Rule Three), and secure."--Jesse's blog, A Method to Your Madness