Although I'm sure many are already aware, for those who aren't, I'd like to recommend Kikopup's channel on Youtube. She covers just about every situation or behavior problem (including proofing) you'd come across and she shows you how to train in a fun, rewarding way. Training is enjoyable for both you AND your dog.

You don't need a clicker. Clicker training really means that you use a behavior marker. So you can click a pen, click your tongue, say a special word (Short and precise works best. I find that using an upbeat, high pitched tone of voice makes it distinctive), you can even flash a light for deaf dogs, etc.

Kikopup's channel: http://www.youtube.com/user/kikopup?feature=results_main

It's also a really good idea beef up on dog body language from a qualified source. The better you can understand and communicate with your dog, the better your relationship will be and the better able you'll be to set your dog up for success. I recommend Jean Donaldson's video series: http://www.youtube.com/watch?v=0VmWizZueFQ

Here is a link that might be useful: Kikopup's channel