I suggest learning good by learning the bad things; go through all the deficiency pix on GrowWeedEasy.com a few times, then go through the sick plants and problems forums. You will be surprised how quickly you will learn to diagnose most of the issues we run in to.
Also, look at what the big players are doing. What is Jungle Boys doing? King's Garden? Watch all the episodes of Canna Cribs and Growing Exposed. I have watched all at least once, some of them 5 or 6 times.