To elaborate on "a good set of rings:" You ain'ta'gonna want the $29.99 cheapies in a blister pack. I've always been satisfied with Vortex PMR rings (made by Seekins). $130-150. There are certainly other quality rings, some selling for much more, that others here use and recommend.
So you have a scope and rings... now you need to know how to mount it and the tools with which to do it properly. Scope ring screws are tightened in inch-pounds - not foot-pounds!! -of torque, and they need to be tightened evenly and equally. The most economical way to do this is with a Wheeler FAT driver, $45-60. Other people like other brands and may speak up here. I paid a well-known gunsmith to mount my first Vortex Razor (gen 1 5-20) to insure I knew what to do, purchased the Wheeler tool, and have mounted/dismounted/mounted several scopes many times since then.
You can read a lot here about how to level the reticle during mounting. Do so. For me, I use the level built into the compass on my iPhone. I have compared it to a super-sensitive, high-$ engineering level and found them to be unbelievably close. I level the rail on the rifle and secure the rifle in place, then mount and tighten the bottom rings, then mount the scope itself.
After mounting the scope, I also install a Vortex standard bubble level. Then I put the rifle on a table, point it at a known-plumb vertical edge (such as an actual plumb line or the corner of a building), level the rifle in all planes, insure the vertical reticle is parallel to my known-plumb line, then secure the bubble level in place with its bubble centered.
There are some here who despise a bubble level. I have them on all my rifles and use them with every practice shot. They're mounted where I can see them with my cheek weld established. New shooters are often surprised to learn how much a "fraction of a bubble" translates to horizontal dispersion at 100 yards: if I move my rifle so the left edge of the bubble is touching the left line and put the crosshair on a 1/2" dot at 100 yards, and then cant the rifle so the right edge of the bubble is touching the right line, the crosshair has moved almost 4 inches off the dot. And this is with the bubble still "between the lines." As with rings, avoid cheap knockoffs.
My $0.02. The preceding has worked for me. Other successful shooters may have other recommendations.