Which is the best method we can use in teaching grammar?

Always teach grammar in context. Once students are exposed to a particular structure in a text, you teach them the rule and give them guided practice then free practice. Assess their learning by giving them handouts. In the end set a task for them where they can apply the learned structure.

All education depends on good grammar.  If students cannot understand grammar, they won't read, write or speak clearly in any other area of education, from maths and science to history or geography. Good language is the base on which all other education has to be. Teachers can use a variety of ways to make their grammar lessons memorable and enjoyable for students. Students who enjoy their lessons will pay closer attention, and you will then have an easier time while teaching. 

Teaching English (including grammar) should be done through communicative language teaching. Try to bring life to the classroom as possible. Teach the imperative through total physical response (TPR) or a game: the teacher says. Teach the present continuous through actions in the classroom or TPR. Teach the present simple through authentic material of schedules for classes or trains. Teach the past perfect through acting a story (of the Titanic sinking after hitting an iceberg). Teach past continuous through videos pausing to show a still movement in the middle of an action. Teach conditional through role plays.

Use technology and fun in the classroom. Be aware of multiple intelligence.

Use content-based instruction and task based learning  to make learning meaningful.

Motivate your students to learn.

We cannot choose a method to be the best. Teaching grammar depends on your students level and their creativity.

Think of a funny way that amuses students and motivates them to participate.

1. Write the parts of a grammar rule on pieces of paper. Each part of rule should be written on a single piece of paper. for example, let's teach the first rule of present continuous, so you need4 pieces of paper. you write the pronoun (I) on a piece of paper, (am) on another piece, (V-ing) on a different piece, and then you write (C) on the last piece of paper.

2. write a sentence on different4 pieces of paper (e.g. I am reading a story).

3. put the rule in the correct order on the board and ask your students to order the words of the sentence as they see in the rule. try to scramble the sentence words many times, then keep the sentence to be correct order and scramble the rule parts. Ask your students to look at the sentence and try to re-order the rule.

4. When you make sure they absorbed the correct order of the rule, ask them to write5 sentences and put the rule under each sentence.

5. Write on board5 sentences with scrambled words and ask them to order the words to make correct sentences.

6. write5 sentences, some without (am) and some others without (ing) ending, and ask them to correct them.

Note: If you can provide students with words and pictures on the same piece of paper that help them understand the meaning of words, it will be very helpful and motivating.

Deductive method is the modern trend in teaching grammar " teaching grammar in context"

In my opinion, the best way is to start learning the basic grammar

 I think eclecting  approach which is a combination various approaches and methodologies; such asGrammar Translation Method, Direct Mothed, Audio- visal Method, Bilingual Method, and Communicative Language Teaching- to teach language depending on the aims of the lesson and the abilities of the learners.Different teaching methods are borrowed and adapted to suit the requirement of the learners. It breaks the monotony of the class

The most effective ways to teach grammar is to encourage and promote reading and writing.

To me , it's translation . Get your students translate simple sentences from their language into the target language . This will help them understand the way sentence is built in the language they are learning and understand the grammar they need to use

In my view the best method of teaching grammar is to incorporate interactivity into lessons. Using games to teach grammar not only engages students but also helps them to remember what they’ve learned. This method allows teachers to tailor their lessons to the different learning styles of students. For instance, each student can be given a large flashcard with a word on it, and the students must physically arrange themselves into a proper sentence. Other games can include word puzzles or fun online quizzes.