Write down your idea in as much detail as possible. Include everything, from story to characters to story world to technical specs to possible revenue models to… well, everything you’ve developed so far. Also use this to work on a 30 second pitch (the so called ”elevator pitch”), as this will help you hone your idea considerably. If you can’t explain your idea in a sellable manner in 30 seconds, it’s probably too complex. You can, if you want, take a look at Screen Australia’s template for a Transmedia Production Bible – if nothing else, it will give you some pointers on the areas people will have questions about.
Do some research (which is a point that has been mentioned before) on what else has been made that is similar to your project. Whatever it is that you’ve come up with, chances are someone, somewhere has done something vaguely similar. Study and learn as much as you can from these examples and tweak your idea accordingly, to simply work better. There is also quite a few case studies that can give valuable information – take a look at the Game of Thrones case study or … well, just do a Google search and pick the ones suitable for you!
Look at entry points for collaborators from the outset. If you’re creating something where a novel or a graphic novel (physical or online) is a major part of the property, perhaps approach a publisher or someone connected to a publisher? If a game is an integral part, look at how a game developer could come into your team, and which developer that would be. If it’s an online treasure hunt (as at least 60% of transmedia ideas are wont to be (don’t quote me on that, it’s just a feeling I have J )) then a web agency or suchlike might be the right one to approach. Try to think of the project from their point of view – how can they apply what they know and get the most possible out of it? (This is me guessing you do not have the funding to hire them outright; if you do, call me ;)
Build your network. It can be slow going, finding the right people, getting to talk to them, getting them interested… It’s also hard to get past the initial adversity you might encounter as someone who approaches out of the blue, barging in with a totally new idea that they then have to try to relate to in some way. As everywhere else, personal connections count for a lot. Just to be able to tweet someone to ask for a good sound engineer in the area they live in can save you a lot of time and effort; it’s well worth putting time in to get to know people. In the field of transmedia you could apply for different courses and classes, national and international, where you can not only hone your idea but connect with mentors and likeminded people from all over the place. (There are quite a few, The Pixel Lab for instance, or different training courses). Some might be fairly costly, but applying is usually free and once accepted it’s possible to apply for different kinds of funding and grants. This is one of the upsides of ”transmedia” being a bit of a buzzword at the moment; it is (at least sometimes) easier to convince funders to invest in something that is so clearly pointing to the future, even though not all financial support mechanisms are in place yet. Also, don’t ignore the value of online activity. Most transmedia people are more or less active on social networks and blogs; connect, make contact, offer your thoughts, discuss and share. Just like anywhere else.
It is quite possible, perhaps even likely, that you still will have no traction for your idea after having honed it, worked on it, done your research and built a network. I’d suggest you make something as proof of concept. This proof will a) show a lot more than mere words can say about the essence of your project. It will also b) give you a chance to build a following for whatever you are offering – a following that will give you more leverage when approaching possible sponsors or collaborators. One advice is to look at current trends and try to find some that sync with your idea on some level. Use that trend to get your content, your idea, in front of people, and be prepared to harness those people (in a mutually satisfactory way, naturally) when they decide to invest time in what you have to offer.