There really is no such thing as "best" sound settings. Sound is very subjective. What sounds good to one person may sound bad to another. Also, music genre plays a roll in how you set your sound up, as well as the type of device you are listening through (e.g. one brand/model of earbud will sound different than another and therefore adjustments will have to be made to that specific earbud).
Best is to just play around with the settings until you come up with something you like.