One of the most useful things I can share straight up is a product called “Polymorph” which is great for customised handles on your needles. There are other similar products but for this instance I will only speak of the one I have personally used.
This product melts in boiling water, is mouldable and then goes rock hard in cold water. This is wonderful for making multi needle tools and specialised handles to aid in comfortable grip. The most impressive feature being the fact that you can remelt it to change out a broken needle and reset it. Over and over again till the cows come home!
This was a major game changer for me in my Needle Felting career. I have big ones that have multi needles for smoothing. Single ones for heavy stabbing and they can even be colour coded.
I find that I use my needle very differently for different tasks and with this product I can design the perfect ergonomic handle to reduce the incidence of injury to hands and arms from gripping a narrow needle.
I recommend you do some research and find this product or similar and start giving some serious thought to how you use your needles. This analysis will truly benefit your attention to detail and improve your technique tenfold.
Injury is very real if you don’t pace yourself at first. Holding the needle firmly made the inside edge of my thumb completely numb when I first started. I was afraid the feeling wouldn’t return so I got a good scare. This advice comes from necessity, you know, the mother of invention.
You can purchase "Polymorph" on Amazon.