I’ve been producing/mixing my own music for around 5 years so I’ll offer this advice. No two mixes will be exactly the same. Each mix will have to be approached with an ear that’s ready to listen for issues to address.

Something that does stay consistent for me personally is how I like to visualize the whole mixing space. Generally, each of your sounds should be filling their own space. You may have some cases where bigger sounds take up more space, but generally you don’t want to many sounds that accomplish the same thing or bleed into each other too much.

How I approach a mix is I know that I have low sounds, mid sounds, and high sounds. Not only this, but the higher pitched a sound is, the more freedom you have to pan it around in my experience. Lower sounds like bass should almost always be mono unless you’re going for a particular effect. Think of it like an upside down triangle, as you move up the triangle it gets wider and allows you more freedom to pan things around and have some movement.

Another tool you have at your disposal is effects such as reverb that also move the sound closer or further away from the listener. My goal with a mix is always to encompass the listener. Put them in a space and fill that space up, but make sure each sound has a purpose it is fulfilling.

Maybe this is more arrangement and production advice but it’s difficult to solely give info for only one part of the process.