I've thought about this topic for awhile and am sure that I am not alone. We have all had projects which kept us busy for a period of time and then lost interest or have had to focus on other projects or issues. Now that I look back on the past I realize that a lot can be accomplished by doing things a little bit at a time, taking small steps or when time permits bite off a big chunk of the project.
What I have done is make a rough program (outline w/ details) of how I would like to finish my bug. This includes but not limited to; engine, trans, suspension, brakes(disks?), bodywork, paint, interior, etc. I kept the program simple so changes can be made without difficulty. Also I like to watch how much I can spend at one time $$$$$$$.
As to keeping the interest alive, I spend at least 1/2 hr each day doing something on the bug, even on the days that I feel crappy. Somehow working on that little green bug with the smiley face makes me feel better. I have done several 12+ hr days in a row on the bug to get it on the road. But in the end it was worth it.
I have made up 2 lists, little projects and big projects. Little projects can take about 15min to 1/2hr, ha ha ha you all know how that goes. And the big projects can take longer, complete brake job, body panel repairs, engine work, suspension, and etc.
Well that's it. A lot of you have built a lot of cars and are still doing it. So you have been through this.
Am I OK or do I just have beetlemania.