There are a few simple keys to keeping hanging baskets looking good. The first is proper watering - not too much, and not too little. A good method is to gently lift the plant in the morning. If it lifts easily and feels light, water thoroughly (until water runs out the bottom). If the pot feels solid and heavy, water lightly. If the pot feels very heavy, do not water it! Overwatering is a very common mistake. Check the pot again at the end of the day and water if it is light.
The next key is fertilizing. Hanging baskets usually have lots of flowers and therefore require lots of fertility. Watering every other week with liquid fertilizer (such as fish emulsion) will keep them looking good. We like Neptune's organic fertilizers, though synthetic fertilizers like MiracleGro are more rapidly available to the plants if time is of the essence.
The final key is pruning. If you’ve done proper watering and fertilizing and the plant starts looking leggy or overgrown, give your hanging basket a good haircut to get rid of its unhappy foliage and fertilize it. Within a few weeks it will be nicely filled in with new leaves and flowers. Transplanting into a larger container is also a good method of refreshing the plants.