I do exactly as burdenbound, i touch a grouded part (generally the case or the psu) Make sure to be on anything but carpet/plastic and keep the PSU plugged-in but switch turned off (if the PC is already build and/or almost finish, that wil still provide ground through the wall socket and ensure you'll not be electrocuted at the same time)
Also the main sensible parts are mostly RAM, Motherboard and CPU and GPU, HDD and opticals drives don't really have trouble dealing with EMI as they're mostly shielded by the inside, as For SSD, i don't know but i suspect that good Shielding is used too and PSU, and any fans or controller, or any other devices like water pump or any other piece of equipement aren't affected by an EMI discharge...