Should the volume be kept low or a bit on the higher side during mixing?I am just a beginner so....
Low or somewhere inbetween. Unless you have acoustic treatment like baffles and obsorbers, defusers. If you have the level too high you will 'excite' the room causing potentially standing waves; peaks and troughs that are stationary. If you are sat in either a node or anti node (technical term for aforementioned) you'll end up with a thin sounding mix or bass heavy sounding mix. Theres other things to consider but I've given you the basics of what happens if having your speakers too loud.
