I'm a simple woman with simple preferences, I'd like to think. I'm going to leave out anything skill-related and just focus on specific types of content I adore. 
Fantasy/fantastical elements. What's that? You have a modern story... but with magic?! Sign me up. Stereotypical Western medieval fantasy? I'm still here. Basically, if it's anything fantasy-related, I will give the comic a strong, fighting chance.
Innocent, sweet main characters. Bonus points if you plan to break the cutie in some way, or if the cutie is already broken and the sweetness is a facade.
Deceptively happy aesthetic. I like Madoka... and Higurashi. I'm also a big fan of any other stories that appear to be happy and cheerful, but either take a dramatic or slow and subtle turn towards the macabre.
Romantic subplots. @Chita mentioned this one, but I need to tack it on to my own list because I am a huge sucker for romantic subplots. I have no shame, and I'm not sorry.
Idiots in love. I love watching idiots fumble about in love. Please. Give it to me. I will eat that up.