Include all variable expenses now, car maintenance, electricity, heating, these can vary throughout the year you need to calculate them and come up with an average monthly amount. None essential expenses like eating out coffee at Starbucks, weekend getaways, extravagant vacations, fancy clothing, motorcycles, ATV's, if you use them, write them down, realize these are wants, not needs. Now total these all up, fixed expenses, variable expenses, and non_essential expenses,there you now have your total expenses.
After you have track your spending for a month, you now have the information you need to create a monthly budget. Now you know exactly how and what you spend your money on. If you did not have a surplus of money at the end of the month, you can now see area where you can trim your spending in order to operate you budget with a surplus next month.