All the things you mention all depends on where your hunting, the size of the deer herd, as well as the the buck to doe ratio.
A lot of the hunting you see on TV that sells all these products are on game farms. Not a fair comparison for a fair chase hunt.
I hunt (fair chase) in upstate NY. All a decoy did for me was to stop the deer from coming in. It spooked them and they took off with a snort.
As far as scrapes, all I ever do is find them and leave them alone. I'll set up on a run that leads to that scrape keeping the wind direction and the movement of the deer in mind, or I'll set up thirty yards down wind from the scrape. Keep in mind many scrapes are made at night. Especially if it's a big buck. Hunting his scrape in the day time could prove to be fruitless. I don't hunt rubs. All that tells you is a buck "was" there once. Although, if you find a lot of rubs in the same place that could prove to be eventful. BTW, they also rub at night.
I hunt the does during the rut. That's where the bucks will he headed. You'll need to learn their patterns Feeding, sleeping, mating, etc.
The only scent I use is a good cover scent on my boots to mask my coming and going. Acorn or a red fox urine. What ever is natural to your woods. Get a good scent blocker suit, and always set up with the wind as THE determining factor.
(SOAP BOX TIME)
NOW, WITH ALL THAT SAID, THE "MOST" IMPORTANT THING YOU NEED TO GET IS GOOD AT SHOOTING! PRACTICE! PRACTICE! PRACTICE! AND KEEP ON PRACTICING UNTIL YOUR GOOD ENOUGH TO HIT A SMALL PIE PLATE AT TWENTY YARDS FIVE OUT OF FIVE TIMES.
When you think you're good enough, practice some more. Your going to have a "pucker factor" when that deer gets within twenty yards of your tree stand. The more you practice the more you'll be ready when that big buck comes walking in and it sounds like your heart is beating so hard you swear to God that the deer is going to hear it.
I've seen so many guys hit the woods thinking they're ready to go kill an animal when all they do is wound them. Then they come up with every excuse why it's not their fault. They sell shirts with all those excuses on them. Go buy on of those shirts, that will tell you all the things you'll need to overcome.
I've been bow hunting for over 30 years. I could have wrote that shirt. I start practicing two months before season opens, EVERY YEAR!
Know your yardage. That's important. When that white tail comes in, chances are real good the he isn't going to come in the way you want him to. Murphy's law is alive and well in the woods.
You'll have to learn to shoot squatting, bending backwards, sitting, leaning right and left. Imagine every feasable way of moving your body while up in a tree stand and learn to shoot that way. Ducking under and over tree limbs, around tree trunks.
Practice with your hunting clothes on. Your going to hate the feeling you'll get when you've practiced all summer long in short sleeves and you get out hunting wearing your insulated coverall suit and that monster buck of a life time comes walking within fifteen yards and you some how got your bow at full draw with out him seeing you with your pin dead on his vitals and he doesn't even know your there. You then release while thinking of which taxidermist your going to take him to, only to have the string hit your left sleeve and the arrow flies off high and to the left hitting your monster buck in the non vital portion of his neck. Trust me, you'll hate that feeling.
Know the deers anatomy! If it's a good hit don't get out of your tree for at least thirty minutes from the time you hit him. If it hunches when shot and it bounds away with it's tail up, wait at least thirty minute, quietly get out of your tree stand and exit in the opposite direction the deer went, then wait at least eight hours before tracking. Chance are real good that's a gut shot. If it takes off like a bat out of hell runnin gflat out with it's tail down chances are that's a good hit. Stay in your stand for the half hour.