Well, we know they have to do with spacial referencing, so what about?
EX: Don't fill (your stomach) up on sweets - we're going to eat dinner soon.
EX: Could you fill my car up with gas, please?
EX: Fill up my coffee cup, would ya?
fill in and fill out
EX: Please fill in or fill out this form.
EX: Gee, I better cut back on the sweets. I'm starting to fill out (i.e., gain weight).
Hope that helps.
- For Teachers