If I had to give 5 writing lessons for absolute beginners, they would be
Children's stories
<--- I wrote a writing lesson about this last year.
Introducing a story
Setting a mood
Characterisation
Tone (inc. Show don't tell)
All of these would take much longer to explain at once, than an answer warrants.
For experienced writers you can find my answer to What are some tips for advanced writers?
Don't forget to read books, so you can know what within the scope of writing is possible.
What's an assertion, and what should I type in?
Compesh is a question and answer (and debate) website, so before you make a debate, you better learn what an assertion is. I suppose you already know what a question is, and that you've typed it in the box. ;)
An assertion, is basically a statement you can make, that is either true or false.
Richer people have better health.
The question for that would be, Do richer people have better health?
And don't forget to make your assertion, match your question.
All of these would take much longer to explain at once, than an answer warrants.
For experienced writers you can find my answer to What are some tips for advanced writers?
Don't forget to read books, so you can know what within the scope of writing is possible.