As you will definitely read if you go around the blogs and books related to this subject, the best itch to scratch is your own. However, plenty of people run and have run successful businesses in areas that they didn't know anything about at first; it just makes it harder to succeed.
Find a niche
A common reasoning for this topic are:
- think of something you really wish existed ( problem )
- find out how you could implement/build/create it ( your value proposition )
- go out there and see if anyone else is willing to pay for it ( your market )and how much ( perceived value )
Once you have all that, you can do your math and ask yourself these questions:
- is it a profitable product? can you earn more than what you need to spend?
- is there a market willing to pay? is it big enough to "make it" with, say, 10% market share?
- what are the resources you need to do it?
Built it. Market it. Earn.
After that, if you still think you have a viable product, think again - long and hard. It's hard to learn to say no and recognize ideas for being just that, ideas.
Start. Do you need a team? Then get a team together. Can you hack away a prototype - or even better an MVP? Get going.
- JFDI and get a product out there as fast as you can and confirm your findings above.
Reevaluate. Did things went according to plan? Chances are they didn't. Was it because of your mistakes along the way? Was the business model fundamentally flawed? Was the team not engaged enough? Find your stress point(s) and think whether it's worth fixing.
Personally, I would recommend you read the excellent Business Model Generation
and The Four Steps to Epiphany
books. In my opinion, definite must-reads when trying to get new products that feel customer needs.
There's also quite a few threads here about recommended books, check them out.