The students are bored when they don �t understand why they are studying a subject, whatever it is.
Try to make links between the different subjects : for example it is useful to study English due to the important role of Great Britain and the English language in diplomacy around the world when this country was the Master of the seas.
Try to show the interaction of the different languages showing the common roots between your mother tongue and English.
Try to make the students participate actively to the lesson. For example ask them to prepare a short "lesson" about a grammar point you want to revise. Generally the "teacher" will be very proud and the others more attentive.
Tell them that learning languages is like traveling : when you are able to speak a language you are able to understand the customs of the country in which this language is spoken. When it is a "Latin" language (Italian, Spanish, French...) there are a lot of images in the speaking way whereas "Saxon" languages are more pragmatical, chronological and the speaking way is straighter to the goal : you understand a lot of details with less words. Eastern languages are more creative then Western ones.
Try to make them find texts with which they would like to study.
Invent characters. For one of my students (I give particular lessons) I have invented "Auxiliarus" to personify the auxiliary. We even draw it. That way it was easier for my student to place the words in a sentence.
Well, I confess I try to adapt my teaching to each student and that with only 1 student it is easier. But with a group always use the strength of THE LEADER of this group. If the leader approves your lesson the others will follow.
Hope this may help.