Since I don't have a set monthly income, I keep track of my finances this way:
My paychecks come into my student checking account (debit card) every other wednesday (twice a month)
My Nordstrom and VS bill are almost always due between the 16th and 19th of the month; so for example, if I get paid on the 9th, I obviously don't expect to get paid again until the 23rd. Therefore, I pay those two bills (as much as I can afford, if not the entire balance due) on the 9th, or whatever date my paycheck comes in.
My regular Visa is always due on the 8th, so I pay that right on schedule, or early, since it's an instant transfer through my online banking website.
My cell phone bill is always due on the 21st. This creates a problem, as for some reason, I always get paid AFTER this date. Lucky for me, T-Mobile doesnt' flip out if you don't pay right on time. So I pay that as soon as I get paid, I try not to let it go more than 5-7 days unpaid.
After I've paid these bills, I then go and transfer an amount, usually around 40 or 50 dollars(or more, depending on the check/bonus season), into my savings account.
The rest of the money in my checking account goes to gas/food/personal expenses. I spend about $30ish on gas a week, and I try not to spend much more than $20 on food per week. I keep track in my head and frequently check my online account to make sure I'm not spending too much money on things I don't need to be spending money on.
It's not the most effective system, but it's working for me. You kinda just have to find a system that works for you. My parents both have written checkbook ledgers. I never use these, cuz they're usually wrong lol