How do you make likable a character who is mostly a jerk?
Are they likable? I have one of these. In my story, a brother and sister travel back in time to save their father, and guess what? It's him. I've been asked "why do they even want to go back and save him? He's such a jerk?" Well, I love him. Haha. And he's complicated and does have redeeming qualities. I am actually working on this aspect during revisions, though. I think the way to make a character likable is by letting the reader see different sides of them. A good example of this is Once Upon a Time. The villains in that show are characters you are supposed to hate, they're the bad guys, right? But Regina and Rumple are two of my favorite characters in the show; you know enough about their back stories and see into their minds and their personalities, and again, the redeeming qualities, to help the reader learn to like them.
Do you draw on people you know in real life for characters in your writing?
Nope, haha. Well, not intentionally. I think everyone, to some extent, pulls from their real life, but I don't name characters after anyone I know, nor do I base them on anyone I know, mostly because I do horrible things to my characters that I wouldn't wish upon anyone I know. Sometimes, I might take an aspect of someone that I like (say I'm talking to someone and they are telling me about their job at the local coffee shop, and I like that aspect, so I get it stuck in my head, so I might let a character live in that world a little, but characters, to me, are their own people, people I know like my friends, but I get to play God with them a little, and help them make those good (or bad) life decisions). I get "you should name a character after me!" and I usually answer by saying something along the lines of....you don't want to be one of my characters. Things don't usually turn out well for them.. :-D