Stretch goals - how do you set them and get them done?

I’m in the middle of planning our new marketing strategy for Nozbe for the end of this year and the entire 2016. I need to make this actionable and ambitious and I have a few goals in mind in terms of revenue, customer growth and cutomer happiness. The problem is, there are all stretch goals:

The problem is that if you put too big of a goal you might get discouraged (like I am a little now) that you’re on a track to not making it.

However, a big goal might motivate you to think outside of the box to get your goal done.

That’s why I’m at crossroads now. I really want to find a way to achieving my stretch goals, even though I’m afraid they won’t be reachable. And when I don’t reach them, I’ll think of myself like a failure.

And I want to feel like a winner.

Question: how do you get your goals done?