Answer:
The more you have of me, the less you see. Who am I?
Take one royal word in the plural and make it singular by adding one letter
Take it and you will lose or gain more than all the others.
The little pink nub that helps rectify mistakes.
What is it that you must give before you can keep it
Before I grow I'm small. When I'm old I grow tall. When I die I give a mighty fall.