E-Rank: these jutsu are the general skills every ninja learns at the Ninja Academy. The students are expected to know these skills before graduating to Genin.
Examples: Bunshin no Jutsu, Kawarimi no Jutsu, Henge no Jutsu
D-Rank: these jutsu are Genin-level techniques. These skills will make up most of a Genin's arsenal.
Examples: Kage Shuriken no Jutsu, Juujin Bunshin, Shunshin no Jutsu, Narakumi no Jutsu
C-Rank: these jutsu are Chuunin-level techniques. Some Genin will have one skill at this level, serving as their "trump card" to pass the Chuunin Exams.
Examples: Kuchiyose no Jutsu, Nikudan Sensha, Shintenshin no Jutsu, Shishi Rendan
B-Rank: these jutsu are Jounin-level techniques. Chuunin and Special Jounin are able to utilize most jutsu at this level.
Examples: Kage Bunshin no Jutsu, Omote Renge, Sensatsu Suishou
A-Rank: these jutsu are Jounin-level and forbidden techniques. Some Jounin will develop their own unique jutsu from this level to serve as their "trump card" but these are mainly known to Kage-level ninja.
Examples: Chidori, Tajuu Kage Bunshin no Jutsu, Juin Jutsu, Gogyou Kaiin
S-Rank: these jutsu are the generally forbidden or secret techniques known only to one ninja.
Examples: Edo Tensei, Raikiri
Genjutsu (Illusion Techniques) are techniques that use the chakra in the victim's nervous system to create illusions; an advanced intellectual Ninjutsu. The most commonly seen Genjutsu is simple creation of phantasms- causing the targeted person to hear, see, smell, taste and feel things that are not actually there in order to manipulate them; other applications of Genjutsu are rare.
Ninjutsu (Ninja Techniques) is hard to define; it is basically any technique that does not fall under either Taijutsu or Genjutsu, which means that it uses sources outside those naturally available to the body or the mind to accomplish its task. Ninjutsu relies on chakra and, most of the times, hand seals (Sequential positions the hands are put into in order to mold chakra in the necessary manner to perform a jutsu).
Taijutsu (Body techniques) or more figuratively hand-to-hand combat) refers to any techniques involving the martial arts or the optimisation of natural human abilities in general. In some cases chakra is involved to enhance the techniques, but generally speaking a Taijutsu user can fare well without much chakra available compared to a Genjutsu or Ninjutsu user. See also: real-world Taijutsu, basically a general term for a wide range of martial arts techniques.
Fuuinjutsu (Sealing Techniques) Fuuinjutsu techniques are the sealing techniques of the ninja. They allow the ninja to contain the elements and demons.
Doujutsu- This subcategory is not one of the main skill arts. This jutsu ability stems from the unique qualities of the users genetics. Doujutsu techniques involve jutsu ability found inherent in the eye that do not involve hand seals. Doujutsu techniques have several abilities. It gives one the ability to read Genjutsu, Taijutsu and Ninjutsu and then defeat it. It also gives one the ability to cast jutsu techniques only possible by possessing the eye. The primary users of Doujutsu are the Uchiha Clan, the holders of the Sharingan eye.
Kinjutsu- This subcategory is not one of the main skill arts. Kinjutsu or "Banned techniques" are those jutsu from the three main categories which have been declared forbidden by the village Kage. This can be because of the toll it places on the ninja, or the evil nature of the technique used.
Elements

Katon (Fire)-Katon, or Fire Element, takes the form of fire and flame attacks. These can be fire balls or extended flame throwing.

Suiton (Water)-Suiton, or Water Element, takes the form of water based attacks. These can be walls of water used as shields or water formed into large striking jets.

Fuuton (Wind)-Fuuton, or Wind Element, takes the form of wind based attacks. These can be huge gusts or sustained wind storms.

Doton (Earth)-Doton, or Earth Element, takes the form of earth and mud based attacks. These can be walls made from mud or the ninja maneuvering himself below ground to attack his opponent from below.

Raiton (Lightning)-Raiton, or Lightning Element takes the form of electrical and lightning based attacks

Mokuton (Wood)-Mokuton, or Wood Element, takes the form of wood attacks and defenses. The usage of this elemental style is a hidden technique unique to Shodai Hokage and others who possess his same exact genes. Mokuton is formed through the simultaneous usage of Water and Earth styles.

Hyouton (Ice)-Hyouton, or Ice Element, takes the form of Ice attacks and defenses. The usage of this elemental style has been seen by Haku and ninja from Hidden Snow. Hyouton is formed through the simultaneous usage of Water and Wind styles.