how to teach grammar

Teaching grammar may be the thing that scares native speakers the most. Most people don’t have an in-depth understanding of the grammar of their own language. You may get mainly conversation classes and feel that you’ve lucked out, but teaching grammar doesn’t have to be horrible for you or for your students.
First of all, keep your expectations realistic. You will not have the time or resources to teach your students everything there is to know about tenses or word order or relative clauses, and you were almost certainly not hired to do so.

There are people who are walking dictionaries of grammar rules; most schools wouldn’t want to hire them and even if they did, most students wouldn’t want to be in their classes. Teach them what they need to know to do the practice exercises in the book or on the test and get them to speak. Many students have spent years in English classes in school, focusing on grammar rather intensively, and still need work. Don’t feel you need to finalize everything in your two-hour class.
Next, make sure you prepare so that you yourself understand the grammar point at hand. Check a reference book or ask other teachers – generally non-native speakers will have a better understanding of grammar than many native speakers. If there are practice exercises, do them yourself and THEN check the answers. This will help you anticipate students’ difficulties and avoid embarrassing yourself with a wrong answer…it happens.
Avoid getting into detailed explanations and try to get your students practicing and speaking as soon as possible. Answer questions to the best of your knowledge. It happens that teachers get creative when they don’t know the answer, but what you improvise is likely to come back to haunt you. It’s okay to say you need to check on it and get back to the student .