I don't have any scientific evidence to back me up, but my guess is that most houseplants are killed by watering issues. This is true at least for me.
Unfortunately, there are no hard and fast rules to follow when it comes to watering your plants. Water needs depend highly on the size of the container, the size and variety of plant, the growing season, and the plant's location. Some plants need to be watered almost every other day, while others would quickly drown in those conditions.
So here is my tip for figuring out how much water your plant really needs: water from the bottom. Every few waterings, fill up the plantís tray. Then keep an eye on it. How quickly does the plant draw up the water? Does it sit in water for several days? This will give you a good idea whether that particular plant is thirsty or if it's getting too much water.
I know many books recommend using the "thumb press" technique, in which you press lightly on the soil to see if it's damp. This technique tells you the saturation level of the soil, but it doesn't really speak to the water needs of the plant. Personally, I'd rather get my advice from the horse's mouth.