Meh. for 3d fighters I do way better with a controller. Especially DOA.
I'll stick to joysticks for 2d fighters though, because they tend to have way more arbitrary inputs.
But when I use a joystick, I use an open palm on the sides of the stick. Like to sidestep left I'll flip my entire hand over to the right of the joystick and tap it with the back of my hand. Right side step, I keep my palm upright (like a karate chop I guess) and I tap the joystick. To crouch I just put my open palm on the top and pull it down, etc.
I rarely ever actually grip the joystick. When I do, it's just with the pointer and flipper fingers.