The human eye has a relatively wide field of view—you can see someone approaching from the side through your peripheral vision. When you’re playing a game, your character doesn’t have this same peripheral vision, because you’re playing on a screen that takes up only a portion of your own field of view. That means you won’t see as many enemies coming up the side, or you may even feel motion sick when moving the camera around fast.
Adjusting the oft-ignored Field of View setting can help with this, provided your game offers it. Widening the field of view may add a slight fisheye effect to the edges of the screen, but you’ll be able to see more of the game world, and it may help reduce that nausea. (It’ll also hamper performance a bit, since the game has to render more objects.) The ideal field of view is dependent on the size of your screen, how close you sit to it, and your personal preferences, but anywhere from 90 to 110 degrees is usually a good starting point. Tweak the setting, give yourself some game time to get used to it, and tweak it again if need be.
Anti-aliasing is another one of those settings that isn’t quite so cut-and-dried. As its name suggests, it aims to fix aliasing, or jagged edges in certain objects or textures. If you’ve ever seen a blade of grass or window frame that looked like a blocky mess rather than straight lines, you know what I’m talking about.
There are many forms of anti-aliasing, each with their own pros and cons, and it’s hard to say one is better or worse than another. Most games will give you an option between a few of these. Super-sampling anti-aliasing, or SSAA, is the ideal solution, rendering objects at a higher resolution and then scaling them down—but this comes with a large performance penalty, so most people won’t have the graphical resources to devote to it.
That leaves you with the compromises: MSAA eliminates aliasing along edges, with a more moderate performance hit. TAA can remove the “shimmering” effect you see on some objects, at a lower performance penalty, but comes with some motion blur. FXAA and SMAA are even less resource-intensive, but add even more blur, to the point where I’d personally rather have jaggies than FXAA. And on top of that, many anti-aliasing settings also come with different levels (like 2X, 4X, or 8X) that offer heavier improvement at the cost of performance.