Approaching Sound Design
Sound design is often ignored when it comes to creating adventure games. but it should always be considered as it can help set the correct mood/ambiance/atmosphere for your game.
The first thing to consider is what perspective the sound should be heard from: your playable character or via the camera. If the sounds are heard via the character then character sounds such as footsteps & character sounds/speech should always be centered & roughly at 100% volume*; all other sounds in a scene should get quieter/louder based on characters position from the sound sources originating position & the balance should be controlled over the entire width (x-axis) of the scene.
* give or take a little bit to add a more dynamic feel to the sound.
You should also take into consideration the current floor type; is the character walking on stones, grass, in mud, concrete etc? all of these things will affect the footstep sound & even possibly the characters walking speed. Is the character walking inside of a cave or a valley? if so then sounds should have some reverb on them & or possibly a touch of echo. Is the character walking behind something? if so then the sounds should be somewhat quieter & appear muffled, which could be achieved by applying a filter cutoff to the sounds in question. Don't forget to add fx to speech & action sound files too for use in certain types of areas as it greatly improves the overall feel & quality of your game & makes it more polished & professional overall.