These are some of the most important informational resources for a low tech tank:

An experiment on substrates
http://www.aquariumlife.com.au/showt...+dinosaur+dung

Crypts and their inflorescence
http://www.aquariumlife.com.au/showt...inflorescence/

2Toned's DIY CO2 Sub
http://www.aquariumlife.com.au/showt...Generating-Sub

Discus Eden's Low light Plant List
http://www.aquariumlife.com.au/showt...ow-light-tanks

Discus Eden's Complete List on Plants and tank Companions
http://www.aquariumlife.com.au/showt...ank-companions

My Summary Of Chemistry
http://www.aquariumlife.com.au/showt...anted-Aquarium

Graeme's sharing of Chuck Gadd's Nutrient Deficiency Symptoms
http://www.aquariumlife.com.au/showt...iency-Symptoms

And for the absolute beginner, who has yet to start their tank, the combined effort of Discus Eden, Bardus71 and mr_c265, which is titled: starting a new tank?
http://www.aquariumlife.com.au/showt...ing-a-new-tank