Show some pictures of people doing stuff. "Where are the people? (on the subway) What actions do you see? ( Talk, dance, eat, listen to music, read.) Encourage ss to produce sentences as much as possible.

Try to act this tense. Walk in the middle of the class, and tell the ss 'I am walking' and they are supposed to say 'yes' or 'no'. After doing the same thing with some other words, write the verbs you used on the board and ask ss to mime these words one by one and elicit present continuous using the verbs. Ask does any one of you play the guitar or any musical instrument? Are you playing the guitar now?No! but you play the guitar, you know how to play the guitar.

Here is where we 'explain' the grammar. I would write the formula on the board: Subject+be+verb+ing and ask ss to provide some sentences (which may be repetitive). Then I'll write down on the board the negative form and question form. I'll explain the most frequent usage of this tense (an ongoing action), touch upon some exceptions in spelling, and also tell them about the pronunciation.

Divide the ss into two groups. ask the first group to make sentences, then ask the second group to make the negative form out of that sentence. Do the same thing with making sentences and elicit the question form of the sentence. Then ask them to do the same in pairs and write down the sentences they made.

I will show ss a photo on my phone, and make a sentence about it. Then I will ask ss to do the same. I will write down their mistakes, and when they finish I'll re-explain the parts they had problems with.