As a writer you only have one way to build your character. You’re not a filmographer, or a camera man, so you can’t give us a picture first hand.
What you must do is paint a picture for us in words. so how do we do this, description, and words. The only way that we can see your character, is if you dress him, and tell us in a very drawing way what he/she looks like. It must completely captivate us, and make us want to read more, so we can learn your development of your character/characters.
Many ways of describing your character, is the use of color, and a very key element. We must know the color of his skin, and his eyes, as well as the color of his hair/facial hair, etc.
Then we move onto features. We must describe and release the Character this way, by explaining his face, his nose, and then his ears.
We must explain body build. Does he slouch? or Is a a firm man or woman that stands erect?
After we describe our character, and paint a picture of what our character looks like, we must then move to the cause and effect, plot, etc. Put our painted character in a situation/situations, to build a story.
When we have the situations that our characters are going into, we then will move forward to create a painting of the room, or the outdoors. What is your character in.doing? Colors also are very key in this description as well.
Is the sun golden and resting on the mountain side? and is the room darkened by the shades blocking the window?
How ever your, people, places, and things coincide with each other, you have to paint a picture with only words, and not a paint brush. However you are the Picasso in your story. Paint away.