The main issue with storing wool is making certain that moths don’t get at it. Wool can survive almost anything else.
The best method is sealing it in something airtight. This might be some kind of sealable plastic box, or vacuum bags – the kind that you suck the air out of with your vacuum cleaner. NB: the vacuum method may leave the wool flat and crinkled, but you can restore it by steaming it for a few hours. Place the wool in your freezer for a few days before storage: this should kill off any moth eggs that might inadvertently have got into it (this also works for wool garments that have been infested with moth larva).
However, if you mean raw wool, just off the sheep, don’t seal it in plastic: that will just allow it to stew in the sweat and grease. Might not harm the wool, but no one will want to touch it afterwards. Raw wool should be scoured – cleaned – before long-term storage, and placed in an air-permeable bag – hessian, cotton, or hemp is good, or failing that an open plastic bag – if you’re just taking it to be scoured.