-Take care of your feet- good boots and good SOCKS!
-Cotton kills in colder climates. Don't wear it when doing anything outside.
-I've always thought that carrying a second, or third, sharp knife is much more useful than stopping what you're doing to hone a blade. Good Mora knives can be had for cheap at any number of places.
-I always have a set of good pruning shears on my belt when scouting or hunting. Good for cutting ribcages and pelvic bones, as well as brush.
-Never step on anything you can step over, never step over anything you can step around.
-A Ziploc with a full roll of toilet paper- I use this instead of flagging tape. I hunt public land that's surveyed for logging, and there's ancient flagging tape every-damn-where. The only TP in the tree is mine, and I've got a full roll so I can flag the hell out of every drop of blood. TP is biodegradable. So are crepe paper streamers from party stores.
-Two ways to start a fire. I like the butane 'grill' lighters; I think the bulk is more than made up for by the ease of use with cold, weak, shaking hands. I also carry a magnesium firestarter on the same neck chain as my knife.
-I scout in the pre-season and build brush blinds. I also try to have a few caches (ammo cans) buried in strategic locations with an MRE, drinking water, extra tinder, Sterno cans, etc. I know someone who buys children's toboggans in the springtime and caches them in the woods for hauling out dead animals.
-FRS radio (turned off, bottom of pack) in case you need to call for help. I actually usually never take this hunting but I do take it canoeing in remote areas.
-2 flashlights that take the same batteries (AA) as my GPS- headlamp in my pack, Mini-Mag on my belt, spare batteries in my pack.
-I use blaze orange, or neon pink, nylon surveyor's twine to wrap handles of anything that I might drop. This mostly applies to knives and camo accessories.
-I cut up an old safety vest (lime green, reflective stripes) and sewed the material inside my boonie hat, and inside one of my jackets. If I get lost or injured I can put the hat and jacket on inside-out to make a SAR helo pilot's job easier. I've also seen duck boats with the bottom painted orange, for the same reason.
-When I'm snowmobiling I take extra socks and gloves (vacuum-packed), as well as a small woodburning stove (coffe can with vent holes drilled in the sides) pre-loaded with fuel, also vacuum-packed. That way if I go in the drink and need to warm up, I don't need to hunt for dry fuel. I made up a bunch of stoves once when bored, and they also work great for honey burns when bear hunting. You'll also want some sort of pot to melt snow and boil water.
-Signcutting and tracking are fungible skills. Don't funge them. If the first time you look at the ground all year is when you're trying to find blood drops, you're going to have a hell of a time recovering your animal. Go walk into the woods and follow the first set of tracks you can find, be they human or animal. See how far you can follow them. Try to pick them back up when you loose them. This will also allow you to learn how different animals move at different times of year. Practice at every opportunity and you'll amaze yourself with what you can accomplish.