Welcome, I hope this will help you when starting out with stop motion.
This will be just a few things to keep in mind when getting set up.
First of all, you need a camera, a digital handheld camera, or, what I have more experience with, a webcam. Next, you need a laptop/Pc. You need to connect your webcam/camera into the laptop then, you need...Say, for example if you're working with a webcam, you want to get the webcam driver/software. Okay, now you want to get some stop motion software, there are some free stop motion software out there like Monkey Jam (which doesn't have onion skinning, but other than that it's pretty good) and then there's the Helium Frog Animator, I believe the downside of this piece of software is that it's a little unstable and buggy.
there are more professional software out there that is so much better than free stuff, actually there is something wrong with pretty much every "free" stop mo software, some software that's not free are: Zu3D, Claymation Studio, and more if you just search around for them. The best stop motion software are: Stop Motion Pro (used by the Aardman Animation studio) and DragonFrame (used by professional studios making feature films.)
Okay enough about stop motion software, lets get back to the camera.
Once you've connected your webcam to the laptop, the software should recognize it and then you can adjust the camera settings straight from the laptop. First off you want to make sure you don't have auto settings on, you want to put the exposure and focus setting on manual. Here is why, when you get your camera out having it on automatic settings, you take a frame, then putting your hands in front of the cam to adjust the position of your character, and then taking your hands away from in front of the camera, that makes the camera readjust, and this could cause the lighting to change slightly, and the same with focus, the focus could automatically readjust, causing blurry images. And that is why very many stop motions you see out there have flickering lighting.
Speaking of lighting, another thing is that if you have the natural sunlight coming through the windows, rather than using some artificial lighting setup, the sun could be going behind a cloud or something causing the room to get slightly darker, is another way the lighting will flicker in the final result. You want to be in a dark room (or cover the windows up) and then you want to make your setup.
First of all, you want to get your set ready, go ahead and watch some tutorials on stop motion sets, and get an idea of what a simple set should be like, and once you've got your miniature set, you want to get some desk laps, or studio lights..here is a link to a website supplying studio lights for stop motion and lots more: http://www.animationsupplies.net/
I'm not trying to make a step by step tutorial, this is more about giving you some important tips for making good stop motion animations.
Anyway, with these few tips, you can make a lot better looking stop motion films.
I hope this has been helpful to you, and if I think of more tips, I will make part 2 to this.
That's all for now,
-Stamp Motion Studio