for answering questions and being witty -- look at categories that you think you would know a lot about, rather than simply scrolling through the most recent questions asked to find something to answer (unless you're like a lot of people I know and have a lot of useless knowledge to share with other people). If you're a business person, help with business. If you're the artsy type like me, go for that category. If you answer within categories you know, you can get major bonus points for having the best answer or simply good ratings.