Here are a few things that help me personally stay on point. I get very easily distracted, and if I didn't have these defined, I'd be all over the place.
1. If you got something going, keep at it.
Don't get me wrong. Everybody needs to start somewhere, but if you have something going, and you've been at it for a while, you have a much better chance getting it to work than starting from scratch.
2. Have a clear goal.
What do you want to achieve? How much you want to make? In what time frame?
3. Understand that this is a business.
To get any business going, you'll need a clear plan. What's more, you'll most likely fail multiple times before you see something working out for you.
When you fail, don't quit and move to the next thing. Instead, keep at it. Work out the problems and keep going.
This one is so under rated. There is so much to do and so much pressure, that unless you relax, you'll get really, really tired, really really quickly.
There are plenty other things that I consider to be important, but I didn't want to make this post too long.
Anyway... what else do you think we should add to this list?