Either way will work, the wrist band does the same as touching the case frequently allowing any potential static to discharge to the case frame. If you get a wristband you only need one. It's nothing more than a strap with a piece of metal that touches your skin, connects via a cord and uses a metal clamp to attach to some point on the case. It basically 'touches the case' for you.
As Zerk2012 pointed out, try to avoid building on carpet. Try to hold components like the cpu by the edges rather than pinching it between your fingers rubbing your fingers all over the contacts/pins. That advise has multiple reasons, keeps from static shocking the contacts, keeps from bending pins or getting natural oils from your fingers on the contacts. Try to avoid touching the contacts of ram, gpu pcie connections etc.