Give your characters a strong backstory. It gives them a stronger framework and springboard at the start of the story. It helps your audience better understand where they are coming from.
What makes your characters pop? Is it a quirk, compassion, uniqueness or a flaw? What are their strengths and weaknesses. What traits define them as people?
Give them real humanistic flaws. Don’t apologize for them. Their flaws are like birthmarks.
Ensure they are committed to their cause; for better or worse. Their cause is the only thing that dominates their world. This is relevant to both antagonists and protagonists.
Give them a moral dilemma; an issue with at least two choices of action each of equally strong appeal. Ensure they make a few bad choices along the way; really bad ones. It aggravates the conflict.
Let their goals emerge from their dilemmas. Let their goals change as they navigate through their choices.
Give them a vulnerability; especially your antagonists. It establishes connectivity with your audience. Are they afraid of the dark, flying or catching a cold? Add an element of obsession so their vulnerability is exaggerated and reinforced. A subdued position elicits additional emotion.
Decide whether your main character is active, inactive or reactive. Active characters make planned choices to influence outcomes, while reactive characters act impulsively to situations thrown at them. Inactive characters are unable to act. They may be restrained, blackmailed or in a coma.
Characters have evolved far beyond the standard archetypes, so play with them.