I always feel the next step once you have an idea is to validate it by creating something simple that you can put in front of someone, so they can review and give feedback.

This can come in different forms
1) Verbally describing the solution and getting feedback from target customers
2) Design simple 1 page brochure to describe the solution and it's features.
3) Clickeable prototype using Keynote, Balsamiq or other.

You don't need to build a working solution ... first start on defining what the problem is, and see if anyone cares.

The key to doing this right, is:
1) Don't tell them it's your idea, say it's a friends project and your helping him collect feedback.
2) Only get feedback from your target customer (i.e. Entrepreneurs, VP's of Marketing, etc) - whoever is going to use or pay for it.
3) DONT SELL. If they don't like it, ask why - but don't sell the idea.

Your goal at this stage is to learn. Another tip if you're up for it, is to ask them to give you $20 for early access. Most people don't have the guts to do this, but it's the fastest way to know if you're truly building something of value, or a nice to have.

I covered how to prototype in this answer if you're curious.
https://clarity.fm/questions/933/building-an-mvp-for-an-online-reward-system-for-consultants-freelancers-va-s