One way is to link cells.
You can have XL create the link for you by clicking in the destination cell,
type in an equal sign ( = ),
navigate to the source sheet and click in the cell holding the "original"
data,
and hit <Enter>.
Anything entered in the source cell will be displayed in the destination
(target) cell.
Look at the formula syntax in the target cell, so you can duplicate this
with revisions in other cells, or you can continue to use the above method.
Another method is to go "in-the-other-direction" ... from the source to the
target.
Right click in the source cell and choose "Copy",
Navigate to the target sheet and right click in the target cell, and choose
"Paste Special".
Click on "Paste Link", and you're done!
You'll notice the 2 different methods produce similar BUT *not* exact
formulas.
The "Paste Link" method yields absolute cell references, while the other
creates relative references.