If you want to make a eight-pointed star or a flower with eight-petals, you need a paper with regular octagon shape instead of square. This page shows how to make an origami regular octagon from a square paper.
In this instruction, I used 15cm x 15cm origami paper. Of course, the folding method is independent of paper size.
We live in a paper kingdom
The people rely on paper wisdom
People may speak here
But the papers make it clear
People forced to obey the papers will
Out of control people take the pill
Paper thinks we can't run our own life
They think they can control the strife
Paper made everything a legal matter
We could have left it in mindless chatter
We should fight the papers before we tire
Get the papers and set them on fire
Take over the kingdom again
Let it be ruled by men