Determine the exact nature of your project. This will be helpful later on when you need to show copyright holders in what context their video will be used.
Determine what songs you want to go along with your project. If you're shooting an action movie, a heavy metal song might work. If you're shooting an emotional documentary, some moody instrumental music might be more appropriate. For a wedding, choose beautiful songs or your favorite as a couple.
Find out who owns the copyright to the music you are interested in using. Only the copyright holder may grant permission to use their music in a project.
Look in the liner notes of CDs. They will often tell you what publishing company owns the copyright to particular songs.
Visit the websites for performing rights organizations like the American Society of Composers, Authors and Publishers (ASCAP); Broadcast Music Inc. (BMI); or Society of European Stage Authors & Composers (SESAC). They have databases where you can look up songs to determine who owns the publishing rights.
Visit the U.S. Copyright Office website. They also have a database where you can look up copyrights and find out who is the publisher of particular songs.
Write a letter to the publisher of the music you are looking to use in your project. Include a description of the scene in which the music is intended for and, if possible, a clip of the scene.
Negotiate a fee with the publisher for using their song in your project. Pay the fee and make sure you use the song in the context you described.
If your looking for music for a wedding montage, contact a wedding videography service that specializes in licensing music. They usually have a list of songs readily available and allow you to request songs as well, including sites like Zoom and WedAlert.