Question

How Concave And Convex Mirrors are made ??

Answer 1

a part of a hollow sphere is taken
when the outer surface of the sphere is silvered it is concave mirror in this case reflecting surface will be the inner surface of the mirror
when the inner surface of the sphere is silvered it is convex mirror in this case reflecting surface will be the outer surface of the mirror

Answer 2

take a hollow sphere
silver(polish) outer surface of the sphere  it is concave mirror 
when you polish inner surface it is convex