Also look up such books as "Timing for Animation" by Halas and Whitaker, "Acting for Animators" by Ed Hooks, or "The Animators Workbook" by Richard Williams. Admittedly they aren't specifically geared to stop motion animation, but they do give you an overview of some of the basic theory. Check out any good books on body language, figure out how Derren Brown knows when someone is lying for example by the way they blink at certain places in a conversation or what direction they glance in when they remember a sound, or how to tell if a date is going badly by the position someone is slumped in a chair.
And also bear in mind stop-motion isn't nearly as easy to break into as it used to be 30 years ago, it's a small industry with a lot of graduates in it waiting by a phone, many of whom are having to get fill in jobs doing other things to pay the bills. To get steady work, not only do you have to be better than most of these people- and there are thousands of them, you also have to be able to network like crazy. Look up courses in the Imagine animation directory or on line (try to find ones with a Skillset accreditation if in the UK as that means the industry respect what they do, as many courses out there are ameteur at best) and get a digital camera rig of your own to practice at home on your kitchen table. That's how the most famous names started. Try to get to a stage where you can create 12 seconds of QUALITY animation on ones (industry speak for 24/25 frames a second) as this is an industry standard, unless you're working on features in which case it's 4 seconds of sheer perfection a day.
And you have to have a passion for it, otherwise you'll fall at the first fence.
Hope I haven't depressed you too much, but you have to be tough to survive out there!
I should know, I'm one of the ones that didn't quite make it! I'm now learning CG...