Comb raiser
Assuming your gun is shooting straight but you’re still lacking consistency, the number one upgrade I’d recommend is an adjustable comb raiser. I use both a fixed Kydex riser and a wrap-around webbing style with foam inserts. Don’t bother with the neoprene stock raisers, they’re fine for a shotgun but useless on rifles. You need either bolts or heavy duty Velcro to keep everything locked down.
Installing a Kydex riser is pretty straightforward, again just take your time to follow the instructions. The wrap-around Velcro, tactical version, is a great option if you don’t want to bugger-up your warranty and still provides a rock solid cheek rest when strapped down securely.
Setup and adjustment is simple. Close your eyes, put the corner of your chin on the stock and slide your face down until you get the perfect cheek weld. With your neck muscles, completely relaxed open your eyes! If you’re not looking directly down the centre of the scope you need to keep sanding the foam insert or adjusting the Kydex accordingly.
A rock solid cheek weld and consistent sight picture can transform your shooting. A comb raiser can give you that.