The key to finishing a project is building something that really interest you. Ive done this myself on more than one occasion, buy a project because its somewhat cool, get it home and find out I really have no interest in it. Out of my last 6 projects 3 saw the light of day. My latest project is probably my most daunting personal undertaking, but at the same time the most exciting one Ive taken on.
I agree totally. Everyone has a dream of what it will look like when drivable but many underestimate what it will take to get it there. If you work steadily on a project then the dream evolves in front of you and keeps you working toward the next phase of the project. Having a project you think is cool from beginning to end helps with motivation, especially on ground up projects.
It's like the old expression, "How do you eat an elephant? One bite at a time." I've talked to folks who just get overwhelmed. It's all about breaking it down into the thousands of little tasks and getting them done one at a time. Sounds like I'm the oddball here as I have several different projects going at the same time. I'll get frustrated with one, put it down for a bit, and start tinkering on another for a bit. I'll come back to the first project eventually refreshed and ready to hit it again.