establish correct lighting and composition of subject
determine what your desired plane of focus should be to give sharpness to only the important components of the scene and blur the rest out - you need to think about this and then apply your knowledge of how the tilt-shift lens changes the plane of focus.
set desired aperture, ISO, shutter speed or exposure setting (eg. Av as you want to control the aperture yourself)
then adjust your tilt-shift lens (eg. amount of tilt and amount of rotation) and approximate focus until you have the desired effect
go to Live Preview on the camera by hitting the SET button (assuming you have Live preview enabled on the menu)
with the scene composed exactly how you want it to be, use the rear toggle to move the LCD screen box onto the subject point you wish to be at maximal sharpness
zoom in to 10x then adjust focus manually then either:
you may need minor exposure compensations depending on degree of tilt/shift.
This is heaps of fun - great for portraits, macrophotography, still life and even landscapes which include near and far objects that need to be in focus. I'm very happy I bought the Canon TS-E 90mm f/2.8 tilt-shift lens.
Here I have selected a focus plane to cross through her right hand and her left eye.