At Vegas you may start by betting your favorite numbers or some you just made up. Luck may put you in the win column or send you packing. Small business start ups sometimes take the same chances. If you want to increase your success start up odds, you'll need to come up with real numbers based on hard evidence.
List the amount you intend to spend in each category and figure it's percentage of the total planned expenses. Each week of the month enter your actual expenses.
Every month total each category and figure your budget over or under for each category to refine next month's budget.
The Profit Puzzle Course Workbook can give you some guidance in coming up with the best numbers to bet your small business start up on and come out a winner.