Ask HN: How do you stay focused?

I guess this is just a pretty open ended question: How do you stay focused on your project?

I feel like I always have problems staying focused. It's not that I get distracted and go play video games, or anything. The thing that usually ruins my focus is my project itself. This is something I find myself having to deal with on every project that I start. I think it may be because when I'm starting a fresh web project, there isn't much to it and it's very easy to get side tracked and work on other aspects of the site.

For example, the one thing that usually always steers me off track is Javascript. In my current project that I'm working on, I want to have a Google map and allow users to pinpoint their location on the map. Simply click the map, and update something else with the latitude and longitude of the click. I got this working, but just like every other project, instead of stopping with the rough, but working, code that I had, I continued messing with the Google map API and started to add markers and stuff to the map. Before I know it, I've got a big bad mess of Javascript that I just ended up scrapping in the end anyways.

That's just an example. I also get easily side tracked by CSS (I'm never satisfied with the way my pages look).

So, how do you all stay focused on implementing only your core features initially? Or even after the core is mostly done, how do you stay focused on whatever single thing you're attempting to implement at that time? Have you found that using things like Git help, for some reason? Do certain editors, or work flows help this?

I will admit, I don't usually map out my psuedo code or flow diagrams or anything before starting these. I will jot some things down in my composition book and organize my thoughts, but I don't ever do wire frames, or anything. Has anyone found that these help you stay on track?

Just curious! Thanks.