H is for Hero or Heroine

That's your main character, whoever he or she may be. You might even have two main characters, or, if you're writing a series, you may have multiple main characters, like George R. R. Martin's Song of Ice and Fire. Whoever they are, they're probably the good guys, the people who will change and be changed by the events in the story. Your readers will be rooting for them, worrying over them, possibly even blogging over them! So you best make them worthy and give them characteristics that will help them on the journey but not too helpful, if you know what I mean. Because that journey needs to be a challenge. So maybe give them some hindering characteristics as well. It doesn't matter what but make sure they're not perfect because no one likes to read about perfect people; they're a bore. And remember, sometimes the most flawed heroes are the most memorable. Like Lestat in Interview with a Vampire and The Vampire Lestat. Anne Rice masterfully gave us a vampire to despise in the first book and then turned him into a hero in the second. Now that's magic.