scarcity mindset

I find myself unwilling to share things with people.
I fear they will become better at, have more than, do better than me if I share with them what I am doing/ my secrets.
This has been a recurrent theme in my life.
I desperately want to work on this to become someone that has a mindset of abundance.
I realize that when you give, you receive 10 fold.
Do I stop feeling guilty about not wanting to share and so don’t it?
OR do I work on becoming a person that is willing to share?
How do I tackle this??