As the title suggests, focusing on yourself is the best thing you can do, not only for yourself but for the health and longevity of any relationship. Meeting someone is always exciting, you are learning more about the other person and yourself. Since you don't know much about each other, there is so much to learn! However, there comes a point when you don't have anything else new to find out about each other. Of course, you may learn some new things here and there, but if you aren't active in your own life, things are going to get stale very quickly.
Have you ever found yourself in a situation where you can't make new conversations? For example, they ask you what you did today or how your day was and... you have nothing new to tell them. Or worse, you just say "nothing..". How awkward!
If you're always trying new things and keeping a busy life it works in your favor for several reasons. Firstly, you have something interesting to say when you talk to them next. You have time apart from them, which creates room for them to miss your presence. You are improving yourself, to your own benefit. Maybe gaining new skills, and learning more about yourself. If your friend, partner, etc. is open minded, you can bond with them over doing something new together. Life is too short not to make the most of it. So, take this article as a sign to try that new thing that makes you curious and excited!