Wood treads and risers... Wainscoting and new rail. More light with a skylight?

what i have done is add shelving in couple spots along both sides and if pos make a cubby or two with fagile pieces being protected iside them with plexy glass on front simple led lighting for lighting on shelves or in cubby areas, or go to a wooden stairs if in budget. raw cedar reflects light giving you an amber look to die for in my opinion

This looks like a very narrow stairway. Don't waste your money trying to "decorate" here. You go up and down--you don't linger here. Put your decorating energy and money into something that matters in one of your main rooms.