If you sometimes get frustrated with teaching difficult grammar points then this article may be of interest to you.
The grammar point mentioned in the article is Modal verbs. Below are some MEC resources which might help you teach this.
Advice/Opinions: Should, Ought to – Grammar Reference Unit
Modals of advice – Language Exercise (Level 3)
What do you think I should do? – Listening Exercise (Level 4)
Modal Verbs – Language Exercise (Level 3)
Or if you want to try building mind maps on your computer, you can find free downloads for mind mapping software here.