How to have gravitas?

I’ve been wondering how to cultivate this… especially as I’m quite a ‘casual’ person. I work in the arts, and it’s a fun industry that people tend to choose for love rather than money. The place we work is not corporate.

I want to remain approachable to my team, but feel like I sometimes do myself down by saying things like “you can take my opinion with a pinch of salt, but…” which I heard myself say yesterday.

I’m really interested to hear others views and practical advice on developing a bit more gravitas. I’ve only been a manager for a few years so maybe it partly comes in time??