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 both English and Japanese.
01: Bird (Tori)
02: Boar (Ousu Buta)
03: Dog (Inu)
04: Hare (Usagi)
05: Ram (O-hitsuji)
06: Horse (Uma)
07: Rat (Nezumi)
08: Serpent (Hebi)
09: Dragon (Ryu)
10: Ox (O-Ushi)
11: Tiger (Tora)
12: Monkey (Saru)
Whether from some kind of Advanced Bloodline or incredible skill, Haku (Zabuza's friend), was able to perform Hand Seals with only 1 hand. It is still unexplained exactly how he was able to do this, but we do know Kakashi had never seen anything like it before. This suggests that it is something only made possible with Haku's bloodline, otherwise Kakashi would have probably known about it, but that's just a guess. Below are pictures of the 1 Handed Hand Seals Haku performed.
There are many other Hand Seals, but they work slightly different than the ones shown above. Think of these other ones as finishing seals. Which, 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. Some of these finishing seals can be found below.
The term "finishing seal" is something I completely made up, and isn't intended to sound official. It just makes it a lot easier to explain.
A/N: I wasn't able to put the pictures in, but there's enough description for you anyway.
