Expanding/explaining is hard

Have you ever tried to compare your answer to someone who got a "higher" mark? If that would be the case for me I would definitely do that to check what I missed.

So I have a problem, and it's affecting all of my essay-based subjects (such as RE, History and obvs English). The problem is that I do not expand enough according to my teacher, they tell me I try to fit in all of the ideas that I have and do not properly expand on any of the ideas well.

My problem is, is that I do not seem to recognise when I don't expand enough, I read it through and think 'okay yh this seems like I'm definitely explaining to a baby using high vocab' (basically to me it seems like I expanded on everything and explained everything). However, clearly to all my teachers that is not the case. I have tried for 2 years to 'improve' (and I say 'improve' as it's clearly not working) and nothing positive comes out of it.

I know my content, explanation is the point where I'm stuck in, i tried following teacher's exemplar answers to no avail. Someone please give me tips as to how to expand/explain well in English/history/re/ in general!!!

A good starting point on expanding your answers is by first establishing your main point (when you're answering an essay-based question) - this makes it clear what you're gonna write in your answer so the teacher/examiner isn't confused. Then expand your point by either a) talking about how you got to that point in the first place/ your reasoning behind it b) talking more about the actual topic, although I wouldn't recommend this too much as you're susceptible to waffling and that may not end well.
Improving in things like this requires continuous effort and practice, PMT has good practice papers and you can also usually find them from exam-based workbooks too.
I hope that helps and good luck!