A logo should satisfy the following points :

1. It should be simple, and yet rich.
2. It should be recognisable, and yet unusual.
3. It should be memorable, and yet apt.
4. It should be contemporary, and yet timeless.

A logo remains just a design on paper but becomes effective only when  an organisation backs it up and supports it. A truly effective logo is associated with many positive qualities such as warmth, care, sophistication, naturalness, power and so on.