During the seed generation, you have the option of enabling hints. These are sold by NPCs and provide information on the locations of important skills.
The most common form of hints are the Zone Hints sold by Lupo. If you buy Lupo’s map of an area, instead of giving you an item Lupo will give you a hint which will tell you how many Key Items are in this area. Key Items include every skill, plus Clean Water and Water Breath.
If you speak to Lupo in his house at Glades, on top of selling Zone Hints for Woods and Glades, Lupo will also sell a hint revealing the zones in which you can find the skills Water Dash, Burrow, Grenade, and Flap. The price of this hint starts at 4000 Spirit Light and will decrease if you already own some of these skills.
Opher is also selling a hint for Clean Water, Glide, Bash and Bow instead of selling Water Breath. In order to unlock this hint, you first need to complete Wellspring's escape and then buy it from Opher at 2500 Spirit Light. Like for Lupo’s hint, the price will decrease if you already have some of the skills related to this hint.
After buying these hints, you can press Alt+P or open your map to display them again.