All activities within the ELT classroom should, ideally, be task-based. In this way, using the English language becomes secondary to completing the task, and hence more meaningful. Compare, for example, asking students to work in pairs and talk about their families to asking students to get the relevant information from their partners in order to draw a family tree. The latter approach is much more likely to produce more use of -- and more useful -- language.
Observing and being observed is essential to developing as an English language teacher. From watching other teachers, you can pick up useful and effective ways of doing things that you otherwise would not have thought of. And, from being observed, you will gain a different perspective on your lessons and become aware of aspects of your personal teaching style that can be improved on as well as those that are working well. Seek out opportunities to both observe experienced teachers and be observed by them to improve your teaching ability and effectiveness.
The three Ps are presentation, practice and production, and refer to how a standard English language lesson should progress. First, a good English language teacher will present new language in an appropriate manner before moving onto an activity where students practice using this new language under controlled circumstances. Last comes the production section, where students are encouraged to use the language they have acquired in a less-controlled activity that gives them freer rein and the leeway to make mistakes. Your lessons need not always follow this three-part approach, but it's a good ideal to strive for.
Games are an important weapon in the English language teacher's arsenal and should not be used as merely a treat or reward. Instead, you should be looking for opportunities to appropriately incorporate them into your lessons. Games provide motivation and interest for students tiring of the hard work of learning another language. They also provide ways for students to use language in a meaningful way as they compete in a game setting. Games can also encourage repeated use of a language item.