I've had this problem many a time, as I'm sure is known by the many threads I've had in this section. Always somehow lose interest because other ideas pop into my head. would have liked to have continued my WCW thread but I just lost interest even though I love WCW. Guess the planning wasn't all there. Now, I've decided to try something I've always wanted to book but never did because I never knew how to go about it. Now I have a fair idea, I'm going to give it a go, got loads of plans for it, loads of good ones too I think. I know you like the year 2004 and you've had a fair few attempts at it, don't see many 04 threads around these waters, maybe look at Kintaro's 04 thread for inspiration? He did his pretty well.
Kintaro has done pretty well, but I've heard there's another good 2004 thread going around that gets updated about once every 2-3 months.
As for the whole getting new ideas and changing threads, it has happened to me numerous times in the past. And I do mean NUMEROUS times. I don't think there's an actual strategy or what not that goes into making a thread the one that sticks. People mention planning, but that's not the way to stick to a thread. It will help, but at the end of the day, if you don't plan, you're an idiot. Almost everybody plans yet it still rarely results in a succesful thread.
For me personally, I feel as if there is not one thing that makes you stick to a thread. I didn't change the way I prepared for 2004 compared to all my failed projects before it, something just clicked. And as cheesy as it sounds, I think it's simply when you find the right thread, you just sort of know because even when these new ideas pop into my head, and I may explore them a little, realistically there's no way I'm leaving 2004. I don't know what it is, it's just something in my head telling me to stick with it.
No idea if any of this made sense, but it's passed my bed time so bad luck.