1. You should always research the different types of fish you are going to be housing together. Certain fish can be extremely aggressive and cannot be paired with other fish of different temperaments.
2. Make sure that the bottom of your aquarium is fully supported by your aquarium stand. If you have any gaps in the structural integrity of your aquarium, it is much more prone to breaks and leaks.
3. Research the aquarium equipment you are looking at before you purchase it. Different sizes of aquariums require different pumps and heaters. Find out which products are best for your aquarium before you start ordering the wrong products.