Quote Originally Posted by stickygreenlightsabr
You should weigh the pot after you've watered it or just pick it up and get a feel for it. You should water when the top couple inches of soil are dry, at this point notice how much it weighs and remember that next time you plan on watering.

That seems to work for a lot of people.
I like this method a lot.. feel the soil and then lift the pot.. if your 2 year old sister can lift it, it needs water

lol