Under past performance the Government picks winners based on their track records and not just the promises in their proposals. This makes a lot of sense and is the way commercial companies often pick vendors. The result has been significant --- companies pay much more attention to successful performance and customer satisfaction because they know their past performance evaluations are riding on it.
The problem with past performance evaluations is that they make it difficult for new companies to do business with the Government. In effect, they have no track record to evaluate. In theory, these companies are not penalized, they are merely given "neutral" past performance ratings. In truth, this is the kiss of death.
If you are a company without previous Government contract experience, you can still pass a past performance evaluation. But you have to understand the process to make it work. Most past performance evaluations follow the process recommended by the Office of Federal Procurement Policy (OFPP), which has published a best practices manual for conducting past performance reviews.
Often the evaluation of past performance includes a survey of customer projects that are similar to the work being proposed. The main focus points of this survey include whether you submitted deliverables on time and whether you completed the project within budget. You can emulate a past performance evaluation by identifying work you have done that is similar to the work required by the Government procurement, and completing the survey yourself.
Often commercial projects and Government projects use different terminology to describe essentially the same things. To make it easy for the Government to evaluate, you should use their terminology. You should present your commercial projects in the terminology used on the past performance survey form. You should also describe your project's scope, processes, and requirements using the terminology of the RFP. Finally, you should also align the project's attributes with the evaluation criteria described in the RFP for the procurement.
Your project description should read like it was a Government project, even though the customer was a commercial customer. The main difference between commercial and Government projects is often that Government projects have more structure. Government project processes are usually formal and documented, as are milestones and deliverables. Making your commercial projects read like Government projects may mean emphasizing the structure of your processes, milestones, and deliverables.
Finally, on a past performance evaluation, the Government may call the customer. You must make sure that the customer is aware they may call, that they phone number you supply works, and it is a good idea to know what the customer might say about you. A successful past performance evaluation requires the participation of your customers, an imposition commercial companies are often reluctant to make. You might want to send the customer a copy of the survey form so they'll know what is coming.