It’s a regular part of my practice and I’m pretty proficient now. I’ll never catch up to decades of practice with my strong hand, but I can do well with my support hand now.
Dry fire and practice your draw frequently to get rid of the “odd” feeling of using your support hand…repetition is key.
One huge piece of advice I can give to help you hit your target more accurately, more frequently is to shift your vision/sighting to align with your non dominant hand. In other words, really concentrate on using your right side vision for firing right handed and your left side vision for firing left handed…this helped me the most in the accuracy department.
I was really trying to sight with my right side vision (since I’m right eye dominant) while shooting left handed which caused major issues in sight alignment. Once I learned to focus my vision to align with my sights, my shooting improved drastically.
And yes, I shoot with both eyes open, but shifting and focusing vision still occurs. You may want to do what I had to do to train myself which is to actually close the eye that you don’t want to focus through while aiming. Shift back and forth repeatedly from left to right.
This actually worked for me as crazy as it sounds.
And a good .22 pistol is golden for learning to shoot with your non dominant hand. Lots and lots of live fire/mag changes, loading etc.