So there are no misunderstandings, create a formal list of house rules, or type up a behavior contract that you and your teen sign. Post the list or contract on the fridge or in another central location where your kids won't be able to miss it.
Examples of clear rules include: "Curfew is 8 p.m. on weekdays, 10 p.m. on weekends, and no going out until homework is finished." Spell out the consequences, too: "Anyone who breaks one of these rules loses television for a day." If your kids do fall out of line, all you have to do is point to the list.