IELTS writing / the main problems

[Lucas]

Hi,

I thought I could ask you, the writers of IELTS essays letters and Ac Task 1, what you see as the main hurdles to successful writing and why?

Many of my students struggle with (in no particular order)
sentence structure
punctuation
passive voice
adj / adv
task response
lack of ideas
formal / informal language
what kind of examples to include
and many more

What about you?