When you're first setting up your fish tank the most important thing you can do is evaluate where you're going to place it. After all, it's a heck of a lot easier to move before you get it filled up with water! The place that you choose for your tank needs to be on level ground, away from windows that receives direct sunlight, and in an area of the house that is not heavily frequented - a hallway next to the front door is not the ideal place for a fish tank.
Being on level ground is the most important of the above criteria. A fish tank that is on an uneven surface has a greater change of cracking because of unequal stress points. In addition to placing it on a level surface, you should also consider adding a sheet of Styrofoam between the bottom of the tank and the stand - especially if you have a larger tank. This will prevent the bottom from bowing out with the weight of the water, which has the potential to lead to a cracked tank bottom.
The next to criteria, no heavily trafficked areas or direct sunlight, will make your life a lot easier. To start with, a tank that is placed in a heavily frequented area is more prone to breaking simply because there is a greater opportunity for an accident to occur. Less commotion also means that your fish are less likely to become stressed with all the outside movement - you can sometimes disregard this if you have a very personable, outgoing fish (like some species of large South American Cichlids and Goldfish).
Placing a tank next to a window that receives direct sunlight will increase the amount of green algae that will grow. While most types of algae are not harmful to your fish, it's pretty hard to see into your fish tank when the glass is completely covered with a thick mat of green fuzz. In other words, avoiding windows is more important for aesthetic reasons.
So, before you get everything set up and filled with water make sure you remember to take a minute and evaluate where your placing your fish tank from a fish's point of view. You'd be surprised at how much frustration simply planning ahead can avoid!