First I create my protagonist, set up his personality, abilities & overall journey/missions, and then create characters around him, plot wise.
Main characters
Protagonist & also the story-driven characters: mostly his parent, or someone who always near and support him, or a catalyst character he met in later story. They mostly have goals, ideals and some have regrets. Their performances are important.
Side characters
Not crucial but they have their place in the plots, as they helps the story going. Some of them even have goals/motives on-panels. Side characters can be colorful.
Minor characters
They have some presence in the story but are secondaries. They're 2 dimensional. Some are just comic reliefs. Some may have names but most don't.
Background characters
No names. Mostly crowds. They are to make the world, the place more lively and believable.