My advice FWIW, is to not over-gun and (probably just as importantly) not over-scope. I've seen far more guys miss animals or hit them badly because all that they could see was hair when they pulled up on a bull at 45 yds and had their optic set on 12x, than I have guys miss a shot at 175 or 200 set on 1.5x... I'd far rather have a good 1-4 or 1.5-5 than a 3-9 or 4-12 any day of the week, magnification doesn't help you shoot better, it just lets you see better. I have 10x binos for looking at stuff...
As to not over-gunning - buy a rifle that you're not afraid to shoot, either physically (everyone has a recoil threshold - even they hairy-chested he-men shooting the big magnums), or financially (I have a friend who only fires 2 shots before season because his .338 ammo "costs so much" - coincidentally, he has missed more animals than anyone else that I know - and those shots are almost never within 12" of each other but they're "good enough", sadly this is pretty common. No, I do not hunt with this individual, but get lots of first hand accounts from his brother. Get a rifle that you can get common ammo for and that you will shoot until you're comfortable with it.
It also really helps if you have a similar rifle in .22LR so that you can practice position shooting and not break the bank - I start my hunting-specific shooting practice in June/July and hit the range with a rimfire and my hunting rifle, usually a .308, but sometimes an 8mm-06, a .280 or a .30-06 - I try for weekly, but most times it's twice a month. I shoot 6" (25/50) & 8" (100m) paper plates and don't use the bench after initial zero confirmation. I then fire 40 rds each at 25/50 & 100m, 10 ea at prone, sitting, kneeling and standing at each range, and don't consider it a win unless I hit minimum 100% at 25 & 50 and 75-80% at 100. I repeat the exercise with the centerfire firing 2 shots per position at each range and look for the same results - sometimes I go home disappointed.
That's 120 rounds of LR and 24 rds of centerfire twice a month for 12-24 weeks. If that isn't an incentive to handload, I'm not sure what is
Shoot more, obsess over caliber less...