I think Swampmonster answered most of your questions. I live in Montana, so I'll tackle a few other points...

Deer leases are not something you should worry too much about given that you're a newbie and living in Idaho. Idaho is filled with public land so you've got all kinds of country at your finger tips just begging to be hunted. Leases are mostly for open-land-challenged states like TX and IL, where so much land is private that getting hunting access can be a real bear.

Forget about trophy size your first few years. Fill tags and learn to care for and cook venison, which has to be the core reason why you hunt in the first place.

One question you might want to think about is whether you're more interested in mule deer or whitetails. You can hunt both there in ID, but the better areas for hunting them vary with which deer catches your fancy. Speaking broadly, you'll find better muley hunting from Boise south, and better whitetail hunting to the north. I stress "speaking broadly", because you'll find some mule deer in every area of ID. You may also find good pockets of whitetails in the south.

Talk to Fish and Game guys - find their number in your hunting regs. Oh, and become an expert on the hunting regs. Idaho's regulations are probably above average in complexity, more complex than Montana's certainly. But that complexity yields opportunity. Many, many hunters trudge along doing the same old thing when great opportunities await just across the next mountain range if only they researched their hunting regs more carefully.

One final note: hunting mags can be a real dead end for someone in the Northwest. In fact, most articles are best used as a backup toilet paper supply, since they focus so heavily on private land farms in Illinois or Kansas. (I speak of whitetail hunting here.) Much of your premo whitetail land in northern ID is so far removed from a farm situation that you really almost need to throw out the magazines. Big woods hunting (like in north ID) is another animal from setting on a funnel between soy bean fields like the magazines are so big on.

Anyway, good luck and keep at it. I'm psyched that you've made the choice to enter our wonderful world of hunting. Enjoy the woods and let the results take care of themselves, even if it takes years. (I needed five years to kill my first deer.) Again, go have some fun!