Buy a book or dictionary of signs. The American Sign Language University has a free online dictionary that has pictures and definitions (see Resources).
Take a class online or in a classroom setting. Classes often build knowledge in a structure that enables you to learn quickly. Start American Sign Language offers a free online course (see Resources). Consider buying a learning DVD as another option.
Practice with a friend to reinforce what you have learned. We often start to lose knowledge that we do not put into practice.
Practice signing to music as lyrics are generally sung slower than regular speech.
Practice signing in a mirror. Since sign language is based solely on seeing, paying attention to facial expressions and body movements is important as well.
Create practice ASL sentences and write out the English translations to learn the differences in ASL and English grammar. You do not sign every word that you say in English.
Master finger spelling early on. Finger spelling is the manual alphabet and is used to communicate names, places and ideas that do not have specific signs.