Your denims should be a proper fit. This means that around the waist and hips, the fit should be comfortable. Not too tight and definitely not lose! Narrow, slim or regular fit will do the job well depending on your body type. Also, get it tailored if you are not happy with the size.
The length should end around your ankles or even if it’s lower, remember to cuff it! In fact this adds more spunk. But there are dress shoes so the cuff should be really neat.
Okay remember, by dress shoes I am not authorizing oxfords! Those are all formal. Try brogues and derbies. Or dress boots too will do really well. In case of loafers, avoid penny loafers. They are formal and go well with casuals but do not add any flame to your denims. Try tassels or horse-bit loafs.
Wear socks unless its loafers. Because we do not want your feet to stink. Wear no show socks for loafers.
Your shoes can be leather or suede. But remember, if you wish to look sharp, keep them polished.