I've been trying to grow mint...

The mint will do better if it does sit outside for a summer. Make sure your soil, indoors and out, is moist and well-drained. Your room temperature should be fairly cool and consistent for best growth. Keep pinching them back as they grow so that they remain compact and in their pots. The nice smell, however, will do best if the mint is kept outdoors. It really needs the living soil and elements to maintain its nice aroma.