Always mark North (N) on the mini map. Even if the player does not know where they are, this will allow them to orientate themselves with a constant point of reference.
The dot/mark/icon representing the player should always be centered on the mini map.
The mini map should rotate as the player does. Or it should be fixed and the player dot/mark/icon rotates instead.
If the mini map does not rotate when the player turns, adding field of vision to the minimap will help the player orientate themselves in relation to north or another landmark.
Quest markers and points of interest can ‘float’ around the edge of the mini map when the player is not in the immediate area. This allows the player to head in the general direction of a marker, without having to open up the full map to check they are on the right course.
Levels and worlds are never completely flat. Give players more information about the destination they are trying to reach by lowering the opacity of the dot/mark/icon when they are above or below it.
Marking the map with the last death location is a great way to help show the player a place they might want to avoid or where they need to go to pick up their dropped loot.
Fog of War (FoW) may be used to mask areas of the map that the player is yet to discover. Once a player has been to a location it is then visible on a map or mini map. A variation of this is to only reveal the part of the map that the player is currently occupying. If the player moves to a new location, they can no longer see what’s happening in the location. Use this to provide an extra level of difficulty or for strategic games in which the player might control multiple units.