Yes, writing can be a tough work.
I usually give some tips to my students before writing an essay.
1/ How to introduce : First of all, People usually say that.., it cannot be denied ect...
2/ How to link ideas: Therefore, it can be inferred that, That's why...
3/ How to clarify something : However, Still, and yet...
4/ How to add another point : moreover, besides, above all, on the one hand ...... on the other hand...
5/ How to add a personal idea : Personally I think, As far as I'm concerned....
6/ opposition : whereas...
7/ How to conclude : To conclude Id like to say that...
To sum up we can finally say that...Last but not least, I'd like to add that...ect...I've a list of writing topics taken from TOEFL that deals with current and varied topics.
The first essays don't usually live up to their expectations but they gradually make progress.
I've noticed that the lack of ideas is my students'major problem!!!