For the sake of simplicity, mecha controls can be divided into three category; control jokes, direct trace input and mental control. Often these are mixed and matched with each other to produce a more sensible and maybe even a more plausible way of controlling your giant robot, but in the end all of them are just as bullshit. The level of sophistication that’s gone in the design can always be appreciated, but in the end there’s nothing much else to it.
Joysticks or similar handles are likely the most common form of controls. You can find these from pretty much any Gundam outside G Gundam, in Muv-Luv’s TSFs, Macross and so on. These controls rely on the basic idea of any control jokes, and I’m sure most people have played some sort of flight simulator with a joystick to understand the basic functions. If not, get yourself two joystics, one for each hand, and boot up Descent in dual-stick control mode. That, or pick up Twin-Sticks for Virtual-On for some TSF gameplay.