One trick, especially useful when learning a new song, is to learn it backwards--that is, last verse first. If there are five verses, learn verse 5 singing it over and over; then learn to do 4 and 5 together; then learn to do 3, 4, and 5 together; then 2, 3, 4, and 5; then 1, 2, 3, 4, and 5.

Doing it this way, you aren't so likely to get hung up where the only way to pick up the thread is to begin at the beginning.

Dave Oesterreich