Just be more optimistic...
You don't have to change your entire image or who you are. An easy thing you can change about yourself today, at this very moment, is your attitude. Find the bright side of every situation. The bright side may not be much better than the other view of the situation, but make yourself focus on the positive--always.
Being optimistic can positively affect your relationships, your sleep, your job performance and more.
Look to those in your life who are always smiling and chance are, they're optimistic people. Just try it out! You can always go back to being pessimistic...I suppose.
FIND YOUR OPTIMISM IN 2015.