Throughout Naruto, the characters use their chakra to generate energy so that they can perform special moves such as Taijutsu (only hand to hand combat), Ninjutsu, Genjutsu and Bloodline Limit jutsu. These are controlled with hand signs (along with chakra) which is gained through experience and your spiritual energy, if you can combine these two with just the right amount of energy, you have the upper chance of defeating your enermy, along with a good set of brains too.
Chakra is the resulting form of energy produced when Physical and Spiritual energies are mixed together within the body. Then to use it, Hand Seals are performed. This allows the user to expel it out the body in the form of an attack, and requires different Hand Seals for different attacks. It takes time and lots of training to gradually build up and being able to control it. Too much chakra and it could result in a poorly executed justu.
Taijutsu is in fact the only justsu which does not require chakra but conclusively just your own experience from training, just hand to hand combat.
Chakra is the resulting form of energy when 2 other energies are mixed together, having those other 2 energies become more powerful, will in-turn make the Chakra more powerful.
To perform most attacks, hand seals combined with chakra are used. Each of the main hand seals is based on an animal from the Chinese Zodiac, and shown below are a picture of that hand seal along with the name in English.
1. Rooster 2. Boar 3. Dog 4. Dragon 5. Hare 6. Horse 7. Monkey 8.Ox 9. Ram 10.Rat 11. Snake 12. Tiger
1. 2. 3.
4. 5. 6.
7. 8. 9.
There are many other Hand Seals, but they work slightly different than the ones shown above. They are like finishing seals. Instead of being a used in many different jutsus, they're designated to their own specific jutsu, and appear after all the regular Hand Seals are made.
Generally speaking, jutsu are divided into three categories: Taijutsu (Body techniques), Genjutsu (Mind techniques) and Ninjutsu (Techniques that rely on sources beyond those). Besides these main categories there is another, more specific category: Fûin jutsu (Sealing techniques).
Besides being either Ninjutsu, Taijutsu or Genjutsu a jutsu can also be "Hiden" ( Secret). Hiden jutsu are jutsu passed down from generation to generation within some clans. There is technically another category called Kinjutsu (Forbidden Techniques), but it refers not to the type of the jutsu but to the fact that it is forbidden to learn or perform it.
A technique can be categorized as kinjutsu if it either causes great harm to the user if overused, such as Rock Lee's Lotus techniques, or if the techniques are dark or sinister in nature, such as many of Orochimaru's skills. There are also Kekkei genkai. These are not really jutsu, but special, genetically inherited abilities like the ability to copy other jutsu or to merge your body with other bodies. Kekkei genkai abilities that work via the user's eye are called Dojutsu (Pupil Techniques). Some jutsu are based on Kekkei Genkai, like Tsukuyomi.
Ninjutsu vaguely refers to pretty much any technique that uses chakra and allows the user to do something that they otherwise would be incapable of doing. Unlike genjutsu, which makes the opponent see illusions, the effects of ninjutsu are quite real. Ninjutsu relies on chakra and, most of the time, hand seals to be effective. The hands are put in sequential positions that mold chakra in the necessary manner to perform a jutsu.
This is not always consistent, however, and some of the simpler jutsu seem to become second nature to experienced ninja, after which they can perform them at will. Additionally, some ninjutsu can be classified as an elemental jutsu, in those cases where a specific element (wind, water, fire, earth, lightning) is used.
Genjutsu are techniques that use the chakra in the victim's nervous system to create illusions; an advanced intellectual ninjutsu. Those with special abilities like the Uchiha clan's Sharingan or those with high intelligence have an easier time executing genjutsu, since attention to detail is key. The most commonly seen genjutsu is the simple creation of phantasms causing the targeted person(s) to hear, see, smell, taste and/or feel sensations that are not actually there in order to manipulate them. In other words, genjutsu affects the five senses, though other applications of genjutsu exist. Those under the influence of genjutsu either freeze in place or lose consciousness, depending on how capable they are on recognizing and defending against it.
There are several ways to counter genjutsu. Because it uses the victim's own chakra against them, the target can cancel the genjutsu by disrupting their own chakra flow. This is called Genjutsu Cancel. Alternatively, should they fail to cancel the genjutsu, intense pain can snap them out of it. Finally, someone else can disrupt their chakra flow for them through physical contact. The level of a genjutsu determines the difficulty in breaking it.
Taijutsu refers to any techniques involving the martial arts or the optimization of natural human abilities in general. In other words, taijutsu is executed by accessing the user's stamina directly, rather than converting the user's stamina to chakra in order to execute a ninjutsu or genjutsu technique, meaning that taijutsu is much quicker to execute than (though potentially not as powerful as) ninjutsu or genjutsu.
In some cases, chakra is used to enhance the techniques, particularly in the Hyuga clan's Gentle Fist style. Generally speaking, however, a taijutsu user rarely uses chakra in their attacks.
Fūin jutsu are jutsu that 'seal' something inside objects or living beings.
Juin jutsu "cursed seal techniques" are jutsu that use a special 'cursed seal' to put someone under the control of the user.
Kekkei Genkai are abilities passed down genetically in specific clans. Most clans have developed special jutsu related to their kekkei genkai (like Neji Hyuga's Eight Trigram Palms Heavenly Spin or Kimimaro Kaguya's Dance of the Seedling Fern).
Kekkei genkai and their related jutsu cannot be taught or copied by others, as they require the specific trait to work. Kekkei genkai abilities that work via the user's eye are called dōjutsu.