The first year for me is the year to prototype as much as possible. Do the MVP (minimum viable product) with quality and track down analytics to the user engagement.
Start with the core idea and build out worth. The less features the better. Make the essential and remove all non essencial features.
The goal for the first year is to prove that there is a market/need for your idea. If it doesn't grow on it's own, then probably you need to tweak it and adjust your initial idea.
Users should bring users. Users should come back. If that doesn't happen, then probably you are working on something that can make all the logic in the world but that users don't want or need.
In a nut shell, the first year is trial and error. Analytics, tune up, change, try again, until you reach a consistent growth.