The general rule for tropical plants is that they tend to survive with more water rather than not enough.
This can be a slippery slope. Sure, they do prefer to have their soil stay evenly saturated. Just don't allow your flora to sit in water.
Proper watering and lighting are the most important components of indoor plant care, but humidity and temperatures also play a role. The trick is to try to mimic the climate of the place that plant came from.
Tropical plants thrive in warm, humid environments, while cacti and succulents prefer hot, dry climes.
Have a look at the care tips blog.