First is something commonly liked; competent characters. They don't need to be good at everything, but they need to have at least one thing that they're really skilled at. It also has to be something that has importance to the story, so I can see the character is useful and not a burden.
And this is a personal preference, but cautious characters. I dislike reckless characters who make random assumptions and have zero patience. I like characters who take their time to check their info, and are always open to the idea that they may be wrong. I like characters who don't take stupid risks, or at least properly weigh them, who prioritize keeping what they have now.
Of course, they don't have to be like that all the time. Faced with emotional turmoil or limited time, they may also fail or act recklessly. They just have to be competent and cautious most of the time.
