The single best way to build a stable income and to make your business attractive to private equity buyers is to have recurring cashflows. In practice, this means that instead of charging your customers per job, you want them to sign a contract that allows you to provide different services over the course of a year.
The hard part about doing this is figuring out exactly how much the customer's monthly payment will be. Essentially, you have to amortize the cost of your services over a fixed period of time. Here is how you do it in Duranta.