The quick and honest answer is - you don't.
In games, as in many places in the software industry, ideas are worth nothing, only the implementation counts.

In addition, ideas tend to evolve during development and the design you end up implementing in the final game is quite often very different from the one you started with.

To be even more honest - it's likely your idea is not as original as you think. I'm not trying to suggest you're not creative, just that there are a lot of other creative people in the industry and we all have tons of ideas. I have written several game designs in the past, then found that other people implemented the same ideas a while later without knowing me. Sometimes I even discovered my ideas were implemented years before I had them by people I never heard of. That's the life in our business.

Another tip - don't try to sign people on NDAs just for hearing your idea. NDAs are fine if you expose them to code, art and data you have already prepared/collected. These are "implementation" products. Trying to sign people on NDAs for hearing your idea is a newbie move and no industry professional / investor will do it. It will make you look like an amateur.

Ok, so this was the discouraging part, now the encouraging one...

If you have a game idea that you think will rock - just go and try it. You don't need developers to try out a platform game idea, just use one of the MANY quick-builders tools out there. Game Maker is a good option as well as GameSalad Creator.

Often you'll find that what you imagined to be a cool idea might not be as fun to play. Sometimes you'll find that combining two genres into one game, as many ideas tend to be, misses the fun factor both genre had.

Games are about finding a fun factor. Identifying a pattern players enjoy recognizing and following over and over. This is immensely hard, but so rewarding when accomplished. I was in charge of the final project workshop of the Game Studies program in collage for 6 years. I went through this process with many students (including the fear of 'idea theft' at the beginning) - it is worth it every time a new game is born.

As to finding developers - look either between your friends or on internet forums (gamedev.net, indieteamup.com). Both places are good, but projects done with friends have higher success rate by far. You can also locate the nearest IGDA Chapter / Game Hackathon (like Global Game Jam) and befriend people there.

All in all, I hope you proceed with your game project. Feel free to contact me if you feel I could help in any way.

To put it in a simple way I listed some options from best to less attractive:

1. Best: self publish with your own budget.
2. Partner with another self publishing developer
3. Self publish using mostly PR and Word of Mouth tactics
4. Use a tier 1 Publisher (DeNA, Gree etc)

Why I listed it in this order:

Self publishing with your own budget allows you to control all the ARM model elements (Acquisition, Retention, Monetization) and optimize the game metrics to the exact target audience. It will give you the expertise in house to publish games which is critical to success int he long run and with other games. It does come with a cost of money and a learning fee unless you bring in someone already experienced. But long term it's the right way to go.

Your second best option is to partner with a good developer who already knows to self-publish games, run campaigns and optimize them. They could also partner with you on the marketing costs in exchange of some revenue (after they cover the marketing expense). This means they'll do a good job and will give you the opportunity to learn how to self publish. Of course, who you do the deal with is critical.

If you don't have a big enough marketing budget and no one experienced to hire, you can try to run a word of mouth campaign. This means means you'll need to find a unique feature in your game to make a big story out it and then push it to the media. This can be unique game story, unique visuals, unique gameplay - anything people could relate to and talk/write about. Monument Valley is but one example. It's still a lot of work, though, don't make a mistake.

Last option is going to a publisher. Only do it if you have absolutely no marketing budget, no marketing expertise and if the game fails it won't kill the studio. Because chances are, it won't score big. And I'm talking about the big, serious, tier 1 publishers.

The good publishers will be able to guide you a bit on improving your game and will give you the right KPI goals to aspire to. Most publishers still don't have a clue about how to do it right and will just confuse you, the good ones at least *knows* what they're talking about.

And still, publishers will only care about your game if it'll be an instant hit. It if will, they'll put the budget, the right account manager and push the game seriously. That's the optimal scenario.

In most cases, your game will achieve moderate to good KPIs but not one of an instant hit and this will happen: they won't spend money on publishing it, and will drive traffic to it from their other games. They won't be able to tell you who these players are, so you won't even be able to optimize to the target audience. They will provide you access to their stats system that will give you a lot of vanity metrics but won't allow you to control the A part of the ARM model, rendering the whole funnel useless.

Bottom line: Do your best to self publish, or partner with a good self publishing developer and learn. And good luck! :)