Once a business is turning a profit it is wise to put some money aside to fund future growth.  Use a cash flow forecast to work out when the business will make a surplus.  These retained earnings are the cheapest form of finance.  For sole traders and partnerships the reinvestment of profits may form part of your annual tax planning. 

In many sectors it is common practice to ask for payment at the start of a job to cover materials etc.  If a contract is going to last some time, staged payments at intervals will help to fund the work.  Working out your cash flow needs in advance will ensure that you can pay your suppliers, contractors or staff on time.