Here's a pretty decent video on loose leash walking. I use this technique and also the "Be a tree" method--where I stop all forward movement until the dog stops pulling and looks at me. This takes time to learn. Also please use a harness as it saves wear and tear on the dog's throat while training. There are harnesses that have the leash attach to the front so that as soon as the dog pulls it immediately redirects them back to you.
And remember, puppies have short attention spans and are unable to learn all this stuff quickly and will need review and practice--but don't over do it or both you and the dog will become frustrated. Have baby expectations for baby dogs.
http://www.youtube.com/watch?v=5O5VY7RbsdMAnd YES--get into a good, positive/reward based training class. Make sure that the trainer does not endorse leash popping or other forms of "coercive" training.