Pets and animals are good topics for easy conversations in English. If you have any pets, you can speak about them and whether you prefer dogs or cats or fish. If you don't have a pet, you can talk about the kinds of animals that are native to your country. You can get philosophical and talk about animal rights issues, whether you think animals should be used for scientific testing and what you think about wearing animal furs.
Another topic that lends itself to good conversations is your favorite things. You can talk about your favorite music, your favorite food and anything else you particularly like. Begin the conversation by describing, for example, your favorite sport, game, person, artist or movie star. You can continue the conversation by describing why you like these things so much and what makes them your favorites.
School can be a good topic for English discussions. You can talk about the subjects you enjoy, and the ones you find easiest and most difficult. You can also talk about what makes a good student and what makes a good teacher. Adult students can talk about what their experience was like when they were in school and describe how things have changed since they went to school.
Another way to encourage easy conversation topics is to use flash cards. Every student picks a card and talks about the topic on the card for one minute. For example, one student could choose a card that says, "Talk about the weather today," which will help him practice the present tense. Another could choose, "What do you plan to do this weekend?" which encourages the future tense; or "What did you do yesterday?" which will practice past tense.