I have spent literally thousands of hours with shears.
Square up the fence to the blade, maybe reverse the blade for sharpness
or true it up yourself.
I always liked to set it up to cut 3 layers of newsprint..
Keep it oiled with something close to sewing machine oil.
If it has slight nicks just stone them out.
Dang if I had a buck for every stoke I laid on hand and stomp shears
well I would still be broke, but, at least my knees would still be good.
Keep the guard in place if you have one.
Fingers are expensive to replace.