Any job with customers including fast food would solidify you as an experienced customer service representative, however if you don't have any prior experience with customers on another job you've worked you can always draw up a functional resume which highlights your skills instead of your experience. Many companies look for you to have at least one year of experience if you're not doing an entry level position. Also apply for ENTRY level customer service jobs which will have a high level of training and not expect you to know everything when you're joining the company.