I usually use elephant as a deal-clincher
usually i put my first line with a small hole in the center where i put my elephants.
send the troops and when they clash, some of the enemy will pour into the gap, trying to flank.
that's when i send my elephant in plus a heavy cav or heavy infantry unit
the effect is that usually two enemy units are calculated to get hammered hard, my infantry can push them back, while my exploitation forces hold the gap and rolled them
oh an the elephant, slow march then charge one part of the enemy line literally breaking them apart
that's when the carnage began