For a planted tank, I have written an article (on another forums) regarding some of the things you have to consider. I will simply copy and paste it here.
Edit: Comments/criticisms/replies are most welcome; I've noticed this thread has 30+ views and not one response from anyone else!
So you decided you wanted to start a planted tank, after seeing a beautiful aquascape in the AGA contests, or perhaps in one of Takashi Amano’s Nature World Aquarium books. Hopefully the guide I’m writing here will serve as a primer to jumpstart you into the world of planted aquaria.
Before starting a planted tank, you first must ask yourself: How much work (and subsequently time and money) do I want to invest into a planted tank? Beginners sometimes forget that many tanks that they see in the AGA contests or Takashi Amano's books are high maintenance tanks (i.e. require weekly pruning).
In essence, planted aquaria can take one of two forms: those that are high light tanks, and those that are low light tanks. Regardless of the type of lighting, algae can become a problem in both types of tanks if proper care and maintenance are not observed. Another question that must be asked at this point is: Do I want a low light (and hence lower maintenance (not maintenance free!)) tank, or a higher light (and thus higher maintenance) tank?
In general, there are 3 factors that are required for plant growth:
3) Carbon dioxide
One can imagine these 3 factors like a triangle; a deficit in one or more of any of these 3 factors will result in an imbalance, allowing algae to take advantage of the situation and begin to flourish and grow.