Check out
Fitz's tutorials on PDing. He shows some of his technique/tools there. As well, check out
Plastidip Artists on Facebook. There are some great resources there in the "files" section, and a lot of knowledgeable peoples that can answer your questions more specifically, and more expediently.
For what I've done, I've used a pen-style wood burner to do some engraving, and I've used my dremel as well, especially for smoothing edges and the like. Razors are, of course, a must, and I've seen people used scrolling saws as well for cutting out larger sections of foam.
That's all I've got, though.
Good luck!