Don't Get Ahead of Yourself
Often times when we get an new idea for a project, you start thinking about it. Mostly about how the project will look like once it's completed or how it will reshape over time. And it's done elaborately and very confidently. Stop doing this.
When we start thinking about the finished idea/project, your mind gets the satisfaction that the project is completed. Then this satisfaction starts reflecting in your project's execution. You start lagging behind, because of the satisfaction.
The solution is just starting the project ASAP. Identify the immediate task, execute that. Then the next. Don't get ahead of yourself, just start!
Consider this, you want to get from 0 to p on the real axis (These are your actions). Once you get to p, you've completed your project. Instead of getting to p on the real axis, we get to p on the imaginary axis (These are your thoughts/dreams). You get the mental satisfaction either way. But the objective should be getting to p on the real axis.
So, just start your project already. Act now, dream later!