Be sure your credit history is in proper standing. This will help you get more favorable terms.
Get a copy of your free credit report from one or all of the three major agencies (Equifax, Experian and TransUnion). Check it for accuracy and make sure to fix any problems.
Run your numbers through a couple of different loan calculators to see if you'll benefit from a student loan consolidation. There are many of these calculators available on the Internet.
For federal consolidation, you can apply online. Federal loans should be consolidated separately from private loans, as the rates and terms for federal loans are much better.
For private loan consolidation, it's highly recommended to talk with a loan counselor first.
Shop around. Call your bank and some local lenders. Look around on the Internet, too. There are thousands of companies that offer private loan consolidation.
Compare their loan terms and run your numbers through some calculators again to choose a private consolidation lender that is most favorable to you.