Read over the hymn to familiarize yourself. Look at the background information, usually listed at the end, such as the composer and the tune used. Note if you recognize either.
Stand or sit in a position that allows you to sing well. Good posture will improve your singing.
Listen to get the melody before you start singing. Pay attention to the words of the hymn.
Join in when you are comfortable with the tune. Sing enthusiastically. Lively singing will intensify your worship experience and energize others.
Think about how the hymn relates to your spiritual life. Look for references to the Scriptures and applications to your daily life.