There are several ways of defining your character and their outlook on the world. One method is using an alignment system. A popular one is from Dungeons and Dragons, as well as Bauldur’s Gate. It uses two axes, good to evil, and law to chaos.
Characters of this alignment believe that to ensure the quality of life for everyone, laws must be created, obeyed, and enforced. When people respect the laws and try to help one another, society as a whole prospers. Therefore, lawful good characters tend to strive for those things that will bring the greatest benefit to the most people and cause the least harm. Examples include Superman, Captain America, and Brienne of Tarth.
These characters believe that a balance between law and chaos is important, while upholding a need for good. Given the vast variation of people and forces within the world, their determined pursuit of good does not upset that balance. Doing good comes before anything else, and Law or Chaos can be ignored entirely by people of these alignment. Examples include Wonder Woman, Gandalf, and Shepherd Book.
Chaotic good characters are strong individualists marked by a streak of kindness and altruism. They believe in all the virtues of goodness and right, but that laws and regulations only restrict their actions. Their actions are guided by their own moral compass and not by what society deems is correct. Examples include Robin Hood, Spiderman, and Luna Lovegood.
Order is of the highest importance to characters of this alignment. They believe in a strong, well-ordered leadership, disinterested in whether it is a tyranny or a benevolent ruler. The benefits outweigh any mortal questions raised by their actions. However, it is important to note that most Lawful Neutral characters follow their own personal vision of order and law. Examples include Judge Dredd, Stannis Baratheon, and Amanda Waller.
True neutral characters believe that all forces, good and evil, chaos and law, must be in balance. They very rarely side with any of the alignments, and tend to be interested in their own goals above all. They also tend to side with anyone who will help them to advance their personal goals and motives. Examples include Doctor Manhattan, Jamie Lannister, and the Ents of Lord of the Rings.
Chaotic neutral characters believe that there is little to no order to anything, including their own actions. A moment of altruism can be followed by another of cruelty. They do whatever they want, whenever they want, and care little for the consequences. While some view these people as completely unreliable, they can be extremely loyal to their friends as well. But their own self interests tend to come first and foremost. Examples include Catwoman, Captain Jack Sparrow, and Riddick.
These characters believe in using society and laws to benefit themselves. Completely ruthless in completing their own goals, they will use rules to benefit themselves in the best manner possible. They also tend to have a personal code of honor that can make them marginally trustworthy to certain other alignments. Given that they may be forced to honor an unfavorable contract or oath they have made, lawful evil characters are usually very careful about giving their word. It should be noted they rarely kill if not necessary. Examples include Magneto, Darth Vader, and Dolores Umbridge.
True evil characters are only concerned with themselves and their own advancement. Uncaring as to their actions are seen as lawful or chaotic, they will do just about anything for their own gain. Although they are far less chaotic, they have no qualms about betraying friends and acquaintances for their own gain. They can be extremely manipulative, playing many sides against each other in order to accomplish their goals. Examples include Emperor Palpatine, Cersei Lannister, and Scar.
These characters are the epitome of destruction and chaos. Chaotic evil characters are motivated only by the idea personal gain and pleasure, caring nothing for whomever might get in the way. They tend to be aggressive and violent, though they are far from stupid or insane. Chaotic evil characters just know what they want, and care little about who gets in the way. Examples include The Joker, Gregor Clegane and the Hyenas from the Lion King.
Another system for describing how your character views the world comes from White Wolf games called the Archetype system. They use a system that shows your character’s nature (their true self) and demeanor (the face your character shows the world). A list of the various options can be found here. There are times that they can be the same, though this is rare.
For example, Moliira has the nature of a Survivor, as she has never given up on her own life. However she has the demeanor of a Manipulator as she presents herself as a master of secrets. Lajaka has the nature of Autist, with secrets buried so deeply that even their existence is a secret. She also has the demeanour of a Survivor, who uses her strength and tactical-thinking to make up for lack of opportunity due to low birth. Kale has the nature of a Defender, and the demeanor of a Rogue, who presents himself as a pirate, though he will defend everything he holds dear to his last breath. Mendean presents himself as a Visionary, seeing things that others do not Though his true nature is that of an Analyst, trying to find patterns in the world.