1. Keep plenty of testing kits on hand, if you own a saltwater aquarium you should mainly focus on nitrates, PH, salinity, and phosphate levels. Never be caught off guard, make sure you have plenty of kits available to test the levels.
2. When adding plants to the aquarium, be sure to check the lighting needs. Try to find plants that will fit the pre-existing lighting conditions of your aquarium. You should avoid plants that require much more light than the fish in your aquarium.
3. You should never add uncured live rock to the aquarium. Doing so can release harmful levels of ammonia into your aquarium.