1. It is generally a good practice to purchase the largest aquarium that you can actually afford. A larger aquarium will be less susceptible to quick changes in the chemistry, and will offer much more stability.
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. It is a good idea to clean your aquarium with a soft wash cloth and warm water. The soft cloth will not leave scratches on the inside of your aquarium and will remove any unsightly stains.