I had just implemented a lighting system into the game and thought of adding dark areas. However some were too dark, thought maybe I could lighten up the areas or I could give the player a light source they could turn on and off. Obvious answer is to give the player a flashlight or lantern. Another conditions was that I wanted the light source to be light source all around the character so a flashlight was out. A lantern could work but was not practical or believable for the character to use.
So I thought about what would work for the time period the game is set in. It is set in 1993 where some weird gimmicky toys and clothes existed. That eventually led me to thinking about light-up shoes. Appropriate for the time and makes sense for the character to wear since he is a kid. This was a rare occasion where the time period, setting and character provided the solution for a design problem.
With that decided I could add pitch black areas where the player needs to use the light-up shoes. This helped add an extra dimension to the game and broaden some puzzles. If you are having issues like these. Look at all aspects of the game and a solution will come.
Example of dark area with light-up shoes.