In order to become a better designer, you have to look at the broader picture: you have to work on yourself in every aspect of your life, completely and constantly. You have to aim to be the best version of yourself that you can bring to work every day continuously day after day.
Constant learning – you have to be able to be ready to work on and hone your skill every day for as long as you are breathing. If you do not work on your skill you will inevitably fall behind on your peers and coworkers, being late on new technologies and methodologies. This will be a vicious cycle to escape, as it will only get progressively harder and mentally challenging to get back in the game, with thoughts of your former glory haunting you.
Know your audience – your title does not define you entirely. Whether you are a UI/UX designer, graphic designer, product designer, a mix or something completely different in the sphere of design, you must not fall out on other segments of design. You should be a little bit of everything but still, specialize enough to differentiate yourself. Also, you have to think and feel like your target audience, know what they like, do not like, want and do not want, this is the only way for creating customer-centric products and designs.