I am not giving any sprite for criticism, but I have a question. The lead character in my game is a ex-secret agent turned homeless guy. I tried drawing him, but my results were quite boring. Since he is the main character, I want the sprite to exude SOME character. I drew his face a permenant frown, with a torn T-shirt and jeans, but it still is boring. Can I get some help in telling how he can be made more INTERESTING? (Like Guybrush or Indiana or Hoagie are very interesting to look at, their sprites speak of their character)
Well, as you said you have already tried clothing and facial expressions, one thing that really makes a difference in a character is their posture and gait. You probably remember recognizing a friend by their gait when you haven't been able to see their face.
When you think of Hoagie's posture, it is obvious that he's an easy-going character and it seems that whereever he is, he's just hanging out. Whereas Indiana Jones is looking very alert and ready to go.
A good way to go around the posture issue, is to merely make a silhouette of the character. This way you don't have to worry about the facial expression or the clothes. If you're wondering whether it's a good method or not, make silhouette of Hoagie, Guybrush and Indiana, and you'll see you can very easily recognize them merely by their shape. You will also notice how Hoagie looks interesting because he's fat and short, whereas Guybrush (in CMI) is thin and tall - I mean, look at his ankles!
Brainstorming on Pessi's point, I think an ex-secret agent turned homeless would be totally paranoid. So perhaps he should be habitually sneaking wherever he walks, constantly scanning his environs, and when he stands still it looks like he's ready to bolt for cover at the first sign of trouble (legs apart and slightly bent, arms out, looking over his shoulder).
And another way to make him look more well posh go to SETUP GAME in AGS and click ANTI-ALIAS SPRITES. It makes the character look more professional and cooler.