I use the cellophane to increase the humidity, I don't really use a fan till they're a bit taller, helps keep the stalk strong. I also don't use a light until after they pop out of the soil.
As your plant gets bigger, you'll deffinetly need more light.
All I have ever used is MG so that's not the problem, not the best soil, but it should have been ok in mg. When using miracle grow, just use straight water. Dont add any nutes till plant is a lot bigger. I never use nutes unless I have a deficiency of some sort, just plain old water only. And I only water when the pot its in feels very light weight.

The single most contributing factor to making your plants "grow like they are on steroids" is lighting. Everything else you do keeps it healthy enough to attain the size and quality.
I'm just a novice here on the forums, but read all you can coz there's some really good stuff here by some incredible growers that are alot better then me.