I think the old cliché “ideas are a dime a dozen” is misleading. Thoughts are a dime a dozen, but from my experience, ideas do have value. (If you haven’t done any leg work to demonstrate that your idea will generate revenue, then the value might be minimal, but companies are always looking for ideas.)
As other have stated, the first step is to get a patent. Protect your idea and don’t discuss it with anyone for two reasons: 1) they might steal it, and 2) you’ve got one year from your first “public disclosure” to file for protection—and public disclosure includes telling your best friend.
The likelihood of you bringing your idea to market yourself is slim. However, as I said, companies are always looking for ideas. I’d suggest you investigate businesses that are already operating in the market, and after you’ve been granted a patent, approach them about purchasing or licensing your patent.
This approach has several advantages: 1) You don’t need to build a factory, 2) the companies will probably have market research to validate the viability of the idea, and 3) you’ll be able to generate income without much additional work.
Of course, on the downside, if your idea is the next pet rock, you won’t make as much as you could if you went it alone, but that’s the trade off for reducing your exposure.
The biggest difference between dreamer and an inventor is the courage to execute the idea. There is a risk involved, but if you do nothing, then you’ve only had a thought. It’s the people who move it to the idea stage that see results.
There’s only one way to know if you’re idea has value and that’s to take it to the next level. It takes courage and it takes confidence, but if you have both of those, then it the cost of entry is pretty low.