We have a few things we can do to make sounds in our game more believable. Sound polish comes down to tweaking the volume of sounds, changing the minimum and maximum attenuation distances, and even replacing sounds that you feel don’t sound good.
These are all things we’ve adjusted throughout the project already. For example, on one of our first ambiences, we can adjust the volume or pitch to see what feels right. Or we can change the minimum or maximum distances on the attenuation, add sounds that we may have missed, make sure that certain sounds that are more important are louder than others, etc.
Overall, mixing and sound polish is a very iterative process of just manipulating the values and replacing sounds with other sounds to get a feel for what’s best. You never know how a sound will fit with the rest of the sounds until you place it in the game.