Your thoughts dictate your reality.
I see it in myself, my friends, and my coaching clients. We are all influenced by what we think every day, in the same way that we're influenced by what we eat every day.
If my junk-food intake outweighs my intake of nutritious food then there will be consequences. And by the same token if I'm thinking a lot of unproductive, negative thoughts instead of affirming, encouraging ones, there will be natural consequences for that as well.
Productive thoughts are those that open up opportunities for solutions and growth. Unproductive thoughts are those that shut down opportunities for solutions and growth. "I don't know what to do," is unproductive. "I can figure this out," is productive. "I'm a big fat pig," is unproductive. "I have the power to change," is productive.
3 Tools for a Productive Mindset:
The Gold Star - Acknowledge yourself for the things you do, even if it feels like you could do them longer, better, or more often.
Course-Correct - Have a handful of productive thoughts that you can pull out when you catch yourself engaging in unproductive-thinking.
Habits v. Goals - Take some of the emphasis off of the end-goals and focus more on the habits and routines required to get you there.
Your thoughts dictate your reality. More productive thoughts = a more productive reality.