A dream featuring a hill can imply that you need to put in more effort towards whatever it is that you are trying to accomplish.
If you are standing on a hill top in the dream then this implies that you have achieved a goal or been successful in some part of your waking life, or you have increased awareness or are starting to see the bigger picture. Alternatively, the dream can suggest that you have the means to achieve something.
A dream where you are moving down a hill may imply that you lack self-belief or control, or you are not having an influence in the direction you are taking in some area of your life.
If you move up the hill in the dream then this may highlight restraint in your life, or you are struggling to achieve something. If you are not climbing the hill alone, then this may suggest that you are moving towards a common goal, or you need to embrace the help of those around you in your waking life.