First, I would subscribe to WESTERN HUNTER magazine. Cheap cheap advice for sure.
Second, I would start hanging around western hunting web site forums and stay up date on the units you might be hunting. Keep a log or journal, just buy a cheap old notebook and keep it handy. Write stuff down about your unit, good and bad. Looking in elk forums you can find out about muleys and vice versa sometimes. I keep logs of what is said about particular units that I want to hunt. Some guys talk alot. Some BS. You make the call.
Third, get your gear in order, don't wait until the last minute. It doesnt' do you any good to invest the time and money (and time is money to many) and have things break down because you didn't do the necessary pre-hunt work.
Fourth, practice shooting. Bow or rifle, it doesn't matter. Practice shooting. Practice the shots you might be taking. Off shooting sticks, on uneven ground, laying down, etc. Get a couple of boxes through your rifle and know it out to ranges you are comfortable taking. Every year I try to get two boxes of shells through my hunting rifle in practice. Simple, fun. Shooting in practice is cheap insurance to get a big boy down when you need to. Confidence is key.
Prepare for the unexpected. Dehydration, altitude sicknss, communtication home, there's a million things to be ready for.
Get in touch with biologists, wardens in the units you expect to hunt. They want you to have a safe hunt. They will help you. Ask the right questions right off the bat. Don't be afraid to call them. It's their job to help. Just dont' expect them to tell you a honey-hole of theirs or where a big bull is laid up. Don't ask stupid questions and you won't be wasting their time.
Get maps. Use Google maps. Get BLM and Forest Service maps.
Good luck.