Once those are HONESTLY answered, you should start looking at your idea in as much detail as you possibly can. Don't assume things will work out or that you will figure it out later.. Concretely, what I do is answer the following things: - How will I get my first 10 users/customers? - Out of these 10, the first one to "test" your product/service out, what is their ideal experience? (and then think backwards as to how you can give them that.. non scalable method is fine initially.) - What about the 2nd user? the 3rd user? will the 3rd user benefit in any way because there were already 2 other people before them to use the product.. (network effect)? - Why will the 1st user stick to your product after their first ideal experience? Remember, that most people dont care much about most things... You have to work through things to keep the first user onboard. - Why will the other users out of these 10 stick to your product/service? - How will these 10 users cause other's to use your product? (word of mouth is the best form of growth.) - Once you reach the initial steady state of the product (a point where initial automatic growth stops, current users are happy), what does that look like? And how will you grow from there? (The what does that look like is very important. How will you grow from there is something that can be answered a little later too.. as most ideas never reach that anyways). - Eventually, what is your plan? And if you are doing this for profit, how will that plan allow you to make "enough" money? Again, you should have some idea of this. It doesnt need to be proven/super concrete, but the clearer this is in your mind, the better. Having no idea of this is not good, but you are probably wrong if you are super confident since most ideas evolve quite a bit.
The above is the ideation phase. There are probably tons of things that are missing from the above, but I think the ones above are quite important to answer. In the above, I assume you already know that there is proven demand or there will be demand for your product/idea once people see it.
About the execution phase: - Start with "drawing" what your product/service would be like. - Find a way to get as many people to see it/understand it and give you feedback.. ideally when you, approach someone with it, try and see from their point of view. Try and turn your pitch very specific to them, their problem (which your idea addresses). - The feedback process will most likely change your idea/initial design. It may even end up in you not believing in your idea anymore. This will be a tricky situation to be in. - If you do end up "passing" the above, then you most likely will have a concrete product/service to build. - The actual building varies a lot based on ideas.. so I am not going to comment on that here. - But ideally, while you are building, get as many people interesting in it.. Create maybe a mailing list of people who will be willing to try it out once you are ready. Do whatever, but try and get your initial set of users interested and waiting for you to launch. This will not only boost your confidence, but it will also teach you lots about how difficult it will be to "sell" our product once you have finally made it.
I hope the above helps you.. these are just my thoughts from my personal experiences :) Execution is everything... and it is super hard. You need to really believe in what you are making in order for it to work out.. All the best!!