I don't think you can MAKE a touch screen.
Touch screens are complicated to manufactured and AFAIK it's not something you can make at home.
Typically there are 3 components here: the physical touch screen, a controller which interprets the analog electrical voltags as a logical location, and a microcontroller (or PC) which queries the controller for touch screen activities.
There are infrared LED touch screens which are not based on a coating but rather a frame around the screen, consisting of simply many infrared (invisible) transmitting LEDs on one side and many receivers on the other side, giving a low-resolution X-Y location of your finger by seeing which row/column receivers see a reduction in light exposure. There are issues of light spread, a finger will probably block the light to more than one receiver and light spreading off adjacent rows/columns will probably still illuminate the desired receiver some. It may be best to use highly focused LEDs but I really don't know.