One of the exercises my teacher likes to do with me is to get me to tell her about my day, or my weekend, or what I want to do in the near future. It helps me practice speaking and writing (i.e., creating output) about things that are relevant and familiar to me, as well as focusing on useful language and grammar.
Talking about what you did on the weekend helps with past tenses, next week is for future, current habits practice present continuous. You can use the subjunctive (if… situations) by imagining what you would have done if you had made a different choice or if something else happened (e.g. if I missed the bus this morning, I would have…).
If you don’t have a person to give you feedback, there are plenty of websites where other users will correct your work (e.g. LiveMocha, Lang-8), and you can correct theirs. Alternatively, you could start a blog of your diary entries and invite readers to give you some advice about improving your writing and/or speaking. You could also write about your language learning experiences.
What kind of output exercises do you like to do?