Spread out said blanket
Fold in half length wise or "hot dog" (enrol a kitty to keep the blanket in place)
Fold the first side into the centre
Repeat! I had to readjust to get the centre centred, hah
Fold in half again, the "centre" is the fold.
Sorry for the terrible video and cartoons in the background hahah
Optional; you can fold on half again but the other direction of what you've been doing
Example (but neater)
They store much easily this way
And they stack better too. Approved by princess Lux.