There are a lot of amazing things to develop a character. There are in, fact, as I have learned from my Theories of personality class this semester, more ways to measure personality than there are ways to skin your cat. For real. I will not try to cover all of them, just one for now.
Currently, this is the most popular way to measure personality. The method claims that there are five dimensions of personality that we all have. These dimensions are bi-polar, meaning that you can picture it more like a sliding scale. You will see what I mean when I outline them in a second. The five dimensions are categorized by smaller traits.
Extroversion/introversion: How takative a person is. Generally people score in the middle, being neither highly extroverted, nor introverted. HOWEVER out of all the scales, this one is the easiest for people to be on one end or the other. I personally feel that this is a thing that we are socialized into being, but that is my personal opinion.​
Openness to new Experiences: This is basically how keen a person is on trying new things. Most people score in the middle here. If your the type of person to constantly likes to try new things, go to new places, and see new things, then you will probably sore on the higher end here. I think that this one is pretty self-explanatory, but just for good measure, my brother scores extremely low on this. He hates watching new shows, new foods, and new clothes. Most people score in the mid-range here, and it can be very peculiar. For instance, Bob here may like new foods but hates to travel.​
Personal note: There are a lot of people who hold that being left-winged automatically makes one open to new experience and being right winged makes one closed to new experience. I, however, eschew this notion. Think about it; if your parents were left-wing and your left wing... not much of a difference, now is there? I feel that no political stance has anything to do with openness--I believe that is moot.​
Agreeableness: Now, a lot of the time we think that extroverts are highly agreeable and introverts are crabby, right? WRONG! There is no link between Introversion versus extroversion and agreeableness. That is a nefarious lie propagated by Disney so they can suck your souls out on the Pirates of the Caribbean ride. Kidding... maybe. If you find yourself in fights often, disagreements on a regular, never/rarely forgive, then you, my dear friend, rate low on agreeableness. This is one that (thankfully) most humans score in the middle, but there are a lot that are on either side. As my professor (who has not only a doctrate in this and sociology, but also over 30 years of couseling and personality analysis under his belt) so defty described a low Agreeableness score, 'If you find everyone else is the problem, chances are you are.'​
Conscientiousness: How clean is your desk? How often do you show up on time? How good is your word? That is what this one measures. Most people score in the middle here. It how much you follow the rules. I am grateful that most people are neither sticklers nor scoundrels.​
Personal note: I find no relation between organization and timeliness. Part of that reasoning is I and my father are two of the messiest men you will find. However, we are never late as far it is with us. Mom, however is the cleanest woman you could meet. However, she is chronically late. See what I mean? Its pretty subjective in my opinion.​
Neuroticism: no, its not what you think it is. Remove that stigma, my friend! Neuroticism is how much you express the emotions you feel. While it can be linked to some bad things, there is no link to high scores here and insanity. Actually, a recent study found that those who express their emotions more often are less likely to die of heart attacks an live longer. Why? Because they don't bottle it all in. Its actually better to score in the middle than on either end here.​
Good question. The answer lies within the question. First off, role play is all about building a great character (in my opinion). Hence you are playing a role. Your role will need to have a character that is believable. So, for you this is a chance for you to think about how to make your characters, how they act, think, and so on. If you would like an idea of how this looks, here is a quiz you can take to see about yourself, and that you can take in character to see how they act. Have fun guys and gals.
OCEAN personality test