A helpful tip is to learn the ASL alphabet first and practice fingerspelling. For learning common signs, a frequent suggestion is to attach pictures of signs for things that are used or seen every day directly to the objects. Finding someone to practice with can also be very helpful.
There are many resources for learning sign language, including online dictionaries that clearly demonstrate how each sign is formed or video tutorials on websites such as YouTube.com. Local schools and other institution sometimes offer classes, and libraries and bookstores commonly have books, learning software and videos as aids for those learning sign language.