Employers generally ask for three references, however, because people are difficult to get a hold of, it is a good idea to have a backup reference.
Make sure to select your references strategically, meaning that if you are applying for a job that requires you to have the ability to develop proposals and you do not really have a reference work that can attest to that, then provide a reference from a community association that you are involved with that can speak on your proposal development skills.
It is important to prepare references ahead of time if you are able to. The best time to coach references is right after the interview and you know more about what the job entails and what types of questions your potential employer is going to ask.
Employers utilize references not only to assure them of your strengths, but they also use your references to clear up any concerns that they may have.
After the interview, hopefully you have gained some insight into what the company is looking for and they’ve expressed any concerns that they might have about your experiences, skills and background.