Two things. First, plan out your milestones ahead of time. It's a lot easier to keep your enthusiasm up if you break the project down into smaller projects and just concentrate on the next milestone.
Second, if you're going to do something that requires expertise you don't have, then you need to have a plan to deal with that from day one. Either you're going to get someone to help (with equity, perhaps, if this is a startup), or you develop the expertise yourself. Don't put six months into something thinking the solution for this part will fall from the sky.
Planning. That's it, in a nutshell. Planning is the key step to finishing any project, personal or professional.
Second, if you're going to do something that requires expertise you don't have, then you need to have a plan to deal with that from day one. Either you're going to get someone to help (with equity, perhaps, if this is a startup), or you develop the expertise yourself. Don't put six months into something thinking the solution for this part will fall from the sky.
Planning. That's it, in a nutshell. Planning is the key step to finishing any project, personal or professional.