Where are you trying to grow? Indoors or out? My suggestion is to grow in pots. If in ground it can take over very quickly and can become invasive. See if these help you!
It should grow like a weed! Where are you located? What variety did you plant? Are you planting on a slope, in the ground, or in a pot? Is your dirt clay (mint requires looser soil with good drainage)? Is the pot too small (mint needs room to sprawl). Is it receiving enough water?