If you're jump shooting the edge of a wetland or irrigation ditch - ie. If you're hunting from a blind near or on open water, then decoys and calls are needed to bring the birds to you. You can make this as simple or as complicated as you want. The very best way to learn about decoys and calls is to find a seasoned veteran and have him or her teach you. Hunters now have more options than ever to learn about calls and decoys - video tapes abound and offer excellent training and tips.
Libraries are a good source, as well.
You can spend a fortune on decoys and calls, but they do no good if not probably used and can even make things worse by scaring off the birds. Again, start with simple decoy sets and use the duck call sparingly. Practice, practice, practice. The more time you spend reading and practicing calling and decoying techniques, the more luck you'll have. The most common mistake is overcalling and scaring the birds away.