The first thing I did was write out a list of monthly expenses:
HOUSING:rent/mortgage; each utility
COMMUNICATION: phone; ISP, etc.; postage
TRANSPORTATION: car repair; car insurance; gasoline; registration and inspection
CHARITY: church tithing; charity giving
HOUSEHOLD CASH: food; school lunches; eating out/ movies (entertainment); small household expenses (water filters, paper products, etc.); toiletries/ OTC meds; kid allowances
OTHER: medicines and doctors; clothing; holidays and presents
You have to figure out your own categories, but there are some that are musts. Even if you pay insurance every six months, you take the annual total and divide by 12 months. Even if you don't know what you pay for incidental things like haircuts, everyday household spending, etc., you can make an educated guess.
Then you look at that total. Compare it to your total monthly income. If it covers everything, good for you. If not, you take your income, subtract the bills you MUST pay, like rent and utilities, food, transportation, prescriptions and see what's left. Divide that into the other more flexible categories.
How I track it is - that list guides me: I leave the total amount necessary in my checking to write checks for monthly bills: rent, phone, etc. I take cash out for food, allowances, school lunches, gas, incidentals and eating out, and I put 1/4 of the food money in the Week 1-Food envelope, etc. And then the bills that aren't monthly (like car insurance) I put into another checking account (not our savings account) and keep there until I need to pay that bill. (Total annual divided by 12: like $20 for insurance, $40 for clothing, $100 for medical costs, etc.)
I pay by check for all my bills and car repair, etc. so I have a record (the checks have carbons), and I pay cash for everyday items and put the receipts for gas and food back in the envelope of its category. At the end of the month write down what you spent in total on food, clothing, eating out, etc. based on your cash receipts.
What about when you start this plan and don't have enough to pay a medical bill yet? For the non-monthly account (let's just work with two categories): Example- you know you're saving $40 a month for clothing and $100 a month for car repairs, it's been 6 months and you need to pay $800 for a car repair, then you know you're "borrowing" $200 from the $240 you've saved for clothing. But the next month you'll be putting $140 into the account for those things again, you probably won't have another car repair for awhile, so you are paying the clothing category back. If you keep the three things separate: cash for this month, bills money for this month, future bills like insurance, then you can see easily what assets you have at any time. You can see if you spent money on clothing, or a birthday party, or a car repair, instead of wondering where your money is going (because you have the check carbons and a monthly list of money spent in each category). But the good news is: YOU PAID IN FULL AND DIDN'T CHARGE ANYTHING!
That's how I've been tracking our finances for the last 13 years. It's gotten me out of debt ($25,000 credit card - living on them as a single mom) and helped me plan to pay for what we really needed when money was really tight. Sorry this is so long, but it really works.