I think some things are often overlooked:
1. Persistence. Giving up after a day or two doesn't lend itself to success. For example, in AZ most hunts are 1 week long and they start on Friday. The vast majority of hunters only hunt Friday, Saturday and Sunday morning, then head home Sunday afternoon. You can't kill one if you aren't hunting! Guys who are successful hunt as much of the season as they possibly can.
2. Maximize your hunting time. Hunt
while you are hunting. Goes along with persistence but is different. A lot of guys, especially new guys I take out, get bored easily and start screwing around and/or stop paying attention to the hunt. Guys who are successful spend their time looking for game the whole day, not just a few hours during "peak times." They don't spend all day napping* or checking Facebook on their cell phones.
3. Scouting. It helps a whole lot to know how/where to hunt.
4. Be ready. Try to mimimize the time it takes you from spot to shot. Anything you have to do to get ready to shoot takes time that the deer or game animal may not offer you. I try to carry my rifle as opposed to slinging it when possible. Have accessories like rangefinders or shooting sticks handy- you may not have time to fumble around for them. I try to stay as ready-to-shoot as possible. I've learned over time that the more ready I am, the more animals I shoot. I've seen several get away due to the hunter not being ready.
*Napping is an important part of hunting. But, there is a balance