First the effect level should be equal or nearly equal in volume to the direct signal , and the number of delay repititions shouldn't be much (just the main one which is equal in volume to the direct , and the others fade out quickly).

Setting the delay time is most of the trick , it depends on the song .... A helpful tip is to set it a bit longer than you expect , try the song with slower speeds till you get the effect right , then set it for lower time and speed up gradually up to the right speed.

BTW , what delay pedal do you use ?