While I agree that you should include a subgoal or other financial goal on your streams, I also think you shouldn't put pressure on your audience to achieve these goals. I think your primary focus should be on content improvement; if viewers want to contribute or subscribe, they will. Even while you gain more as you grow more popular, you don't get there by constantly making your audience feel guilty. It's their income at the end of the day. In addition to donations and subscriptions, there are numerous other ways for streamers to make money that are not only FREE, but doesn't guilt trip your audience.