ms wong - you can buy curtains that need no hemming and no top stitching - you just cut them to fit width wise and if you want to can hem the size.
For dds room - I made some imply rod pocket curtains - nothing too fancy..... just measured the length I wanted them ( to floor) and the width of window. ( usually go for twice the width - so you have a little gather)
I needed 5 metres of the fabric to do a hem at the bottom the the pocket at the top for the rod to go through.
Then - cut in half - 2 1/2 metres each. As each side at the selvedge - just turned that over and hemmed it.
Then measured how much I would need for the pocket and a little fabric at top - stitched channel for rod to go through.
Hung them up on the rod and pinned where hem needed to be - trimmed and hemmed.
I then made some tie backs to pull them back to let the light and breeze in - but oyu can buy some metal ones that you just slip the fabric behind that look fab.
Always get my fabric at spotlight. I got fab blockout fabric for dds room.
locations in wa here
spotlight website
spotlight also have service to make all sorts - curtains, blinds etc.
THey also have helpful brochures on how to make various things.
Do good prices on ready made curtains too.