OKay so I passed out early yesterday and forgot to post my part of the sketch trade of Caisson for tigerzbox

lol well then's kinda tough because an actual strong female character is just a strong character period and so I don't really have a magic bullet for writing good characters straight up. And as for common mistakes, all of the most common tropes that exist within stereotypically weak female characters can exist in a strong female character if that character is written well. I guess the biggest mistake is being unaware of the archetypes you're writing and then not being in control of how that comes across to the audience. 

But if you want a general selfcheck when you're writing your lady character whether she's the protag or a supporting character, just keep asking yourself "what are her motivations? what about her past is informing her present? Does she exist on her own? How is she the hero of her own story?"