Self-discipline

I have a tendency to start a story, write a little off it while it's exciting, then letting it dab off as I start another story. Repeat, repeat, repeat. This is a really bad habit of mine that I need to get under control. But how to do that? 

As for my two non-contemporary WIPs, Apocalypse and Mist On the Moor, I have to be in a certain state of mind to write them. I have to want to write either supernatural or fantasy, and mostly these days I find myself not in the mood for that. I'm for contemporary lately. OK, that's fine, I guess I can write on these two whenever the fancy hits me. 

Over to my contemporary stories. How many WIPs do I have lying around? A few. I need to fix myself a schedule and stick to it. A schedule where I finish WIP #1 before moving onto WIP #2, not like not where I skip around to whichever I prefer in the moment. 

How do other authors manage this? 

Is it just me who has a very short attention span? How do I get it under control? I spend a lot longer on stories when I skip around like this, than I would've if I stayed true to one until the finish life before going off to write on another.

I need some self-discipline. That's what this is all about. I'm going to set up a writing schedule, and I'm damn well going to try and stick to it too. I need to stick to it or else I won't really get anything done. 

If anyone, author or reader, have tips to how to manage this, please feel free to comment.