I'm posting this information two ways. This condensed post is for folks who trust my advice and/or already understand spreadsheets. For the folks who want to understand the minutia of this advice, please read the extended version of this post.
Balance your checking account. Create a new spreadsheet with the following column headers:   Date, Check number, Amount, Transaction, Balance, one titled "B," Cleared and Category. Use this formula in the Balance column:   =E1-C2. Fill Down the formula for two screens.
Create a template below this area (at the bottom of the spreadsheet) for fixed and variable expenses arranged by due date. Add all predictable income without dates (use negative numbers).
Copy and Paste three or more copies of the template into the active portion of the spreadsheet. Adjust entries by real dates. Insert other anticipated income and expenses by date. Use real numbers for expenses and bracket income behind Transactions until actually received.
Group expenses under each predictable income. Insert two rows between each grouping. This is your three month financial projection.
Add all real expenses and incomes (as received) along with supporting data. A copy of this information can be Saved As a new name for your annual tax preparation spreadsheet.
Look for the first negative number. Note the date and amount. This amount of money must be earned by the date notated. Otherwise, it's time to find a new biz.
Enough for now,