Playing a child character can be a rewarding experience and also a challenging one. Some people play children characters almost exclusively and some are dipping their toes to it for the first time. Whichever it may be, the following is meant to help give ideas to players new and old, child and adult.
... Why play a child?
Playing a child character can limit what interactions a player may have. Because of laws, it needs to be recognized that child avatars are not allowed to participate in adult sexual situations. For some individuals this is reason enough not to play a child character. For others, this is the exact reason to play a child character. It is simply one of the basic starting questions any player needs to ask themselves when starting to create a character -- What do I want from my RP?
While children aren't able to be in adult situations as such, and that may be exactly the reason to be a child, there are a lot of other things that they can do that may be more of a challenge to incorporate into an adult character.
For example, an adult is going to have a certain level of basic knowledge. No matter how sheltered they are as they grow up there are some things that they will learn. They may have a high number of life experiences and a low number of schooling or training. Or they may be nobles with little life experience of the world on a grand scale but strong skills in reading, writing and formal situations. In either case, adult characters have to have some form of experience and knowledge, simply due to their age. What else have they done with their time?
The opposite is true for children. Older children will have more experience and knowledge than younger children and the closer to adulthood one is the higher amount of knowledge is expected from them. But if you want to play a character that is not yet shaped and is without knowledge, a child is the most direct and accepted way of doing this.
Other reasons people may choose to play a child is the trouble that one may cause or the assumed freedom that some children have with their actions. Some people love the logic that children use and the imaginative worlds they can create. All of this is important to decide -- the what you want to do with your character -- when deciding if you want to play a child character. After you have decided that yes! I do want to play a child! Then you can move onto the 'how'...
... How do you play a child?
Deciding how to play a child and how your child will be in nature is very similar to creating any other form of character. You must choose the personality of the character ( shy and withdrawn or open and curious? ), the knowledge of the child (older and already seen much life has to offer or younger with the world a new place?), and the race of the child.
Personality is important first as it can lead to the rest of the character creation. What you want to accomplish with your child should determine the personality. If you want to find a family, then the personality needs to be one that is open to having a family. If you want to cause trouble and chaos, then the personality needs to be devious and uncaring. And if your child wants to do nothing but listen to stories all day, then a shy child that can disappear into the background may be best.
After you know the personality that will best fit your goals as a player then you can choose other parts that help shape that nature. Things such as age, race and back story. If you choose to play an elf, what kind of elf? Children of elves develop differently then the children of adults. Different forms of elves have different opinions on other races. Opinions and biases that their children may also come to have. Some races are very protective of their youth and wouldn't dare to let them be out on their own, while other races are more of the idea that children need to experience in their own time. What education is a priority and what do they learn by what age is another things to consider.
The culture and influence that a child has had thus far in their life will determine a lot of their personality. So choosing a back story and race that fits the personality you choose is easier then choosing a race and trying to fit it to the personality. It is also easier then to decide what your child knows and doesn't know, how they see the world as a whole and understand it once you have a grasp of the culture they are coming from.
After you know the knowledge, culture, experience, age and parts that make up your child, you simply slip into their mindset. What are their goals and interests? How do they fill their time? What catches their interest and what frightens them into running the other way? You can also consider appearance. Would they have multiple clothing choices or just one? Do they constantly bath or is dirt unnoticed? How do they find food to eat? What are their favorite foods? What have they had the opportunity to try?
.... What can you do with a child character?
So very much.
Children are perfect students. Anything that catches their interest and fascinates them can keep them entertained for hours, days and even be developed into a beloved craft. Using the child's lack of knowledge to the player's advantage means that children can looks for teachers and start to learn crafts. They can ask questions and challenge ways of thought. They can ask for stories and make demands.
But just as with adults, for in character actions there are in character consequences. A child may ask for a scary story but some scary stories feed that wonderful imagination in different ways. Some adults may not have pure purposes and may choose to twist lies the child takes as truth. Children may attempt to cause havoc and chaos and while some adults will smile and laugh others will grumble and try to teach a lesson.
When we were children growing up it was these actions with their consequences -- positive and negative -- that helped to shape who we are today. Playing a child gives a huge opening to be shaped and affected by adults in a way that many adults can't be affected themselves. So let them! This is what builds RP.