Mark an initial pencil point where the first object in the row will be placed.
Draw out the tape measure 24 to 36 inches, starting from this original point, and make pencil marks at a specific length, say, 12 inches. The number you choose will be the length you must use throughout.
Holding the tape in place, count from the first number you chose, a second span of the same length. For example, if you chose 12 inches for your first mark, count another 12 to arrive at 24 inches and make a mark. Continue using the same spacing until you've marked enough points to place all of the objects evenly.