Some basics I always follow:
-Don't ever use a pot witout drainage holes. Water will accumulate in the bottom and your plant will rot. If you don't like regular pots, use the decorative one over the nursery pot.
-Water from the bottom. Unless you are fertilizing, I think it's better to water the plants through the bottom: place the pot (with holes) in a bowl with water and wait until the soild absorbs as much water as it wants: you have better control of how much water is going into the soil, it prevents fungus gnats and it doesn't weight down the soil.
-In doubt, don't water. It's much better to underwater your plants than overwater them. If you are not sure your plants need water, don't do it. Check the soil, wait another day, etc. but most plants die of overwatering but most can overcome being thristy.
-Don't overfertilize either. Adding too much fertilizer will burn your plants. Don't fertilize more often that the bottle suggests -this only applies to soil, I've never had plants in lecca or any hydroponic medium.
-Choose your plants according to your house. Before getting a new plant, instead of thinking "what do I like?", think "what can survive here?". Think of temperature, humidity, direct sun, pets, etc. and then choose a plant that will thrive in that spot. In some places, some plants will die no matter how much you care for them, and it's much easier and satisfying finding a plant that will be happy at your home.
These are the ones I can think of right now.
Any suggestions?