When we see something every day, we're more likely to think about it. Going back to a past blog post of mine about making the decision to change, when we are in the "change mindset," it is easier to make better choices.
Imagine waking up every morning, walking into the bathroom, flicking on the lights, and seeing the number 30. Every day. Don't you think you would be conscious about what you had for breakfast? What about walking to your desk at work, turning on your computer, and seeing the number 30 on a sticky note on your computer. Don't you think you would be conscious about what you ate for lunch? Not to mention maybe feel motivated to work out during your lunch break?
Whatever your goal may be; build muscle, lose fat, drink more water, eat a healthier lunch...WRITE. IT. DOWN. And then post it in a place where you will see it at least once per day.
Whatever your goal may be, write it down. Then make it happen.