The best way to write a letter of recommendation is to start out with a formal greeting, or using "To whom it may concern" if you don’t know the recipient. Follow the greeting with 2-3 sentences of praise for the person you’re recommending.
How important are letters of recommendation? Letters of recommendation are required for almost every graduate school application and are a very important part of the application process. Usually grades and test scores factor in most heavily; however, your letters of recommendation could be the deciding factor in the admission process.