According to NASA, this was the first collision between - in their words - "two intact spacecraft". This suggests that there may had been cases of satellites colliding with a piece of debris before - there is a lot of junk out there, check the second video clip for more on that.

As to what can be done about it, the data on satellite orbits can be shared between all concerned. This is usually the case, but there are limits to sharing such data, for example, when it comes to military spacecraft.

Another good practise is maintaining one's satellites in their intended orbits. This is also being done, but only as long as the craft is in use, and fully operational. However, satellites go defunct sometimes; also, it gets kind of expensive to keep them in precise orbits all the time, once their mission is accomplished, whereupon they are usually left to their own devices, so to speak.

And, of course, we should clean up the junk that's already up there ;)

Satellies rarely if ever collide, at least not while in use. Each satellite is launched with a specific amount of fuel to keep it in the same orbital slot throughout it's lifetime. Since the satellites stay in the same place throughout their lifespan, they wouldn't actually collide.