A large part of choosing to live a more positive life is choosing to change your thought process. Being positive is not synonymous with being naive or "fake" about your happiness. There has to be a balance of realism, human emotion, and passionate action towards achieving your goals. You have to choose to not let your circumstances define who you are or where you want to go in life.
Changing my thought process, as well as my actions and responses to life situations, required a lot of self-reflection. I had to closely observe what negative affirmations I was having that created the negative energy I was putting out. The constant "I can't do it", "this won't possibly work out in my favor", and "my life sucks" immediately created a negative and insecure vibe.
Investing heavily in my faith has also helped with changing my thought process and getting me closer to my goal of living a more positive and peaceful life. Wholeheartedly believe that it will be okay, whatever that means and however that looks to you in your life. The book I'm currently reading,The Power of Positive Thinking by Norman Vincent Peale gives a lot of different practices and testimonies for this, you should check it out.
So, positive affirmations* and "faith, belief, positive thinking, faith in God, faith in other people, faith in yourself, [and] faith in life" are all things that I see as a good foundation, if you will, to a more positive mindset.
How You Respond
It has become crystal clear to me through self-reflection as well as through interacting with other people, that how you react says more about you than anything. Not everything needs a reaction, and I have found that the more I practice feeling indifferent towards rather insignificant situations, the better I feel in the long-run. When you act impulsively and say or do something negative, everyone will remember what you said or did long after the emotion dissolves. Learning to be more conscious with everything that I say and do, and trying harder to understand the energy or intention behind that has definitely helped me change and be a better source of positive energy.
And that is basically the gist of how I try to have more positive energy on a day-to-day basis. I also do little things like incorporate yellow (represents optimism and happiness) into all of my social media, follow accounts that post motivational quotes/sayings (I also have an app that sends me one everyday), meditate/ pray, read my Bible, etc. Basically things that keep positive energy constant throughout my day.
Here are some links to other articles and things that explain this more in depth:
How to Have an Upward and Outward Focus
The Power of Positive Thinking
10 Practical Ways to Raise Your Positive Vibrations