box or slate....I'd say box first. I really love slates, but think a box is much easier to learn and less to mess with when you have to set it down. Its easier to find the right rythm. Though a crystal/aluminum slate is nice with a glass peg so you can keep calling in the rain.
I also use a slate the bulk of my calling and have gotten into making my own though I do really like how a couple of my primos pots run.
There's a couple good videos on how to use both. Primos has one...as does quaker boy....as does the woodhaven video (has some pretty awesome diaphram callers on the woodhaven also, some of those boys soft talk is second to none!).
Learn three calls....a basic yelp, and the soft talk, cluck and purr and you'll kill birds. Its more about rythm than how much you think you need to sound like a turkey. Sounding good impress's judges and buddies, having the right rythm impress's thunderchickens.
one hard lesson I've learned over the years is your first call can be your last. IE, you set up on a gobbling tom roosted still up in the trees and you start calling. Personally Its over rated and I think will hurt you more often than help, continous calling in the tree and going crazy on a fly down cackle. a good morning tree yelp is good enough... "hey good morning sexy I'm over here".... I've gotten to a point where I've put my calls down and taken diaphrams out so i dont over call and my success off the roost has jumped substantially on initial setups. That toms goal is to get you to come to him and first thing in the morning that is exactly what he's doing...gobbling trying to bring his girls to him before he flies down. Once he's on the ground, start working him. I prefer slow and quiet at first and building depending on how the bird reacts. Something you'll learn....the more you call, the more those birds know exactly what leaf, sitting on what acorn by exactly what tree to the enth degree you are on. overcalling is a turkey hunters worst enemy. I love running and gunning, getn them fired up and gobbling like crazy.....learn when to back off and not hammer them and you'll kill birds!
Some other simple tips.
-When it rains go to the green
-keep an eye out for the 'hot lunch program', (manure spreaders). When they're spreading, be set up when he's almost done or shortly there after.
-they ARE patternable...learn the lay of the land and make it easy, if you're where they normally wnat to go to begin with...your odds of success are extremely high and your calling ability will have to be almost nil! Turkeys ARE patternable, this pattern changes as the weeks go by. Being flexible and understanding what's going on and whats to come will help you immensly!
-if you can learn to run them, tubes and wingbones, next to a slate, are by far my most productive calls. Though I sound terrible on a wingbone, there's something magical about them. And if you really cant figure them out..they make some pretty amazing slate call pegs using the small end.
Good luck and post pics!