In the spring, longer days and higher light intensity cause indoor plants to grow more rapidly. Start fertilizing again using a half-strength solution at every other watering.
Prune hard to stimulate new, bushier growth. Repot houseplants when their roots grow through the drainage holes, when the soil mass is filled with roots, when new leaves are smaller than usual, or when the plant wilts between waterings. Put the plant in a container that is one to two inches wider than the original pot.
If the plants are especially lush and full, and the sort you take outside during the summer months, make some cuttings now for summer planting.