You are what you focus on. Or put another way, what you focus on expands. This means that wherever you choose to direct your focus has a major effect on where your life is going. Yes, I said choose because you control your mind. Your mind can be reprogrammed similar to a computer, but it takes some work and consistent applying of habits.
How do you start the day? The way you start the day sets the tone for the rest of the day. Do you roll out of bed and immediately start looking at social media or news on your phone? Do you work out? Do you meditate? Do you write in a journal? You should establish a morning routine that puts you in a positive state of mind that works for you that you commit to every single morning.
What about during the day? Do you have a stressful job? Are you putting out fires all day? Are you bored? Do you focus on taking from people or giving to people? If you don't like where you are spending your time during the day, it's time for you to make a change.
The most important time is your "free time." After 8 hours of sleep and 8 hours of work, the "third 8" is what makes a huge difference. What are you watching? What are you reading? What are you listening to? I like tv as much as anyone, but it is mindless and rarely edifying. I am a huge music fan, but I have largely swapped out songs for podcasts. And who has time for fiction when there are so many great non-fiction books to explore?
In summary, focus is about being in control of what you think about and what you choose to do with your time. You can take small steps now that will provide big payoffs in the future. Make today a great day.