Ninja rank, way to become a kage

The ninja in a hidden village have their own skill levels which help delineate what rank they are. The most talented ninja in the village is generally the Kage who leads the village, the lowest tier is made up of those young individuals training in the ninja academy.
Ninja Academy students like Konohamaru are taught the basic jutsu skills. Once they have mastered the needed skills, they are able to graduate and become actual ninja.  

Genin are the lowest of ninja skill levels. They possess a knowledge of all the basic ninja skills and will do lower C & D rank missions with their Jounin sensei.

The Chuunin is the basic journeyman ninja of the village. These ninja can become field doctors or teachers. They were formerly Genin who were promoted for displaying excellent intelligence, strategy and combat skills in the Chuunin Exam.

 

Chunnin exam

Special Jounin are ninjas who have gained high Jounin-level skills in one area of ninja arts. Ninja attain the rank of Special Jounin through official appointment. 

The Jounin are ninja who are highly skilled in all jutsu skills and arts. The Jounin generally serve as squad commander for mission operations.
http://www.naruto-boards.com/508003/~list-of-ninja 
The village Kage is the strongest ninja in the hidden village. They have excellent chakra and stamina and know the most jutsu techniques. Only the Five Great Shinobi Countries are allowed to call their head ninja by the Kage name.

By Yang WANG