Over the last half century I have "handled" firearms on almost a daily basis. I really can't connect with those who are buying, handling, shooting firearms for the first time. During that period,I've been shot at (&hit) and done the same to others. Since I don't consider my past to qualify me as an "expert" like some highly advertised individuals do, I don't conduct classes or write books.
I spent a couple of hours last weekend dicussing the buying and carrying of a self defense handgun with a similar aged man. I let him fire a few shots with my choice of pistol and answered questions he had about our state laws and reasons for my choices. He commented that he was constantly surprised that I would be talking about some factor of concealed carry and suddenly, the pistol was in my hand. Like it just appeared-no orchestrated movement-just there.
My most valuable advice(in my estimation anyway) was to become comfortable with your weapon. It's not a snake that's trying to bite you. Learn how it feels. Establish an assurance that you control everything the weapon does. Carry it constantly until you don't notice it's presence. Know absolutely when it's safe and when it's clear.
The worst possible thing is to buy a gun and put it on a shelf somewhere, hoping you know how to use it if needed.