boy, where to begin...
Well-worn and broken in with experience handling in the field (all the things - guns, apparel, packs, binos, etc) is the precursor to success. I buy more new kit than anyone. On the planet. LOL. But I use the shit out of it before it ascends to game day kit.
Suppress all guns.
Eye pro.
A shorter gun is better than a lighter weight gun IMHO. There's a balance to be sure - find yours. IE, I had and enjoyed a Javelin bipod but ultimately got rid of it in favor of a heavier Atlas. I have like 5 now. In field shooting I don't often deploy it fully but love having it out front folded up to square my rest on my pack or a stump or whatever else is at hand. Weight penalty is worth it. Plus, it's way easier to deploy one leg for a tree trunk or branch or something.
2.5-10x mag scope (or less) is ideal.
Pack a fresh shirt to change into if you're going on a high effort hike/climb.
A sweet and salty trail mix is the shit.
Know your various rifle carrying positions and strap configurations.
3 position safety is excellent.
Spend time getting the perfect zero, then spend 10x more time shooting at rocks or other things out in the boonies at odd yardages and from odd positions.
Baby wipes are worth 10x their weight in gold.
Buy OnX or other mapping software and be versed in its use, AND have hard copy maps you can actually use. A good ballistics calculator is good too.
Crawdad traps in the truck or back at camp are routinely an added bonus.
Stainless steel doesn't equal zero maintenance.
Keep finger-nail clippers in your pack.
Shooter/spotter practice is always good.
Practice with all kinds of calibers and firearm types. AR's, bolt guns, 22's, shotguns, pistols...do it all the time and chase all different game throughout the year. You'll see your honey holes all throughout the season(s) and develop knowledge of everything from where animals like to be to where the best place to take a dump is.
Tape your muzzle!
Have in the truck or back at camp a decent firearm tool kit and be versed in its use. Be able to do everything from cleaning a gun to re-setting a scope to disassembly & reassembly. Odds are you won't be doing this for yourself, but someone else. They will owe you all the beer when they knock over a bull after you fixed their gun from the tailgate of your truck.
Legacy calibers are never a bad choice.
Forest naps are probably better than punching a tag.
Don't cheap out on ammo, socks, or binoculars.
If hunting with kids, always have a bbq at the truck/camp for a little hot feast. An EZ Up is great if just going for a day trip and weather is imminent. Take the kids across creeks, up hillsides, through timber...make it a crazy adventure. Then feed them hot food. They will never forget and will tell their first hunting story(ies) forever.