Federal acquisition regulations dictate that all government agencies must issue a request for proposal before they award a contract. This gives the various agencies a chance to evaluate multiple companies' pricing and qualifications. By far the most important thing to keep in mind when responding to an RFP is to read it closely and answer each section with the required information. If you don't win the first few contracts, don't give up hope. Your skills will improve with each RFP you prepare. But if after a few you still find the entire process burdensome, you can always hire a professional proposal writer to help you.
For more on RFPs, be sure to read Responding to a Request for Proposal.