Start with a concrete problem and a small example of how you could help. Before buying tools or building a website, learn how people currently handle that problem and whether your proposed result would be useful to them.
Set a time and spending limit. Create a sample using your own or appropriately permitted material, then seek specific feedback through suitable channels. Ask what would need to change for someone to use the service. Praise is encouraging, but it is not the same as a paid commitment or evidence that the work can be delivered reliably.