What do you suggest/use to attach blankets to a wall?

The are several options:

1) ideally the acoustic blankets supposed to be hanging 6 - 12cm away from the wall to allow for air gap.

2) we have a special screw hooks that were designed to keep the blankets away from the wall.
Here is the hook - VG2GO Hook screw from stainless steel

3) another option is to attach a 5 x 10cm (or similar size) wooden stud to the wall first and then use screws to hang the blankets

4) if you do not want to drill holes in the wall and install wooden studs or VB2GO hook screes, we have a universal stands that can support the acoustic blankets independently. Universal stand would also allow you to separate the room, create a treated section or if you get two or three you can create a make-shift portable vocal booth. Here is the Universal Stand – Flex Tee Stand for Acoustic Blankets