How do you prepare a cash flow forecast?

First, decide how far out you want or need to plan for. The idea is to cover for how far you want the money to go, be it a few weeks or a few months. List out your income. For each week or month, list all your income sources, all the cash you have coming in. List all your outgoings, expenses, expenditure, etc. From this, you can work out your cash flow.