I would say the best thing for you to do is read, read, read.Whatever stage ofgrowthyour in, or whatever problems your having, read about it first, post your questions, then read some more. This is a picky plant to grow (If you don't want to waste your time and end up with shwagg) so read everything you can find. Another thing is to ask the store employees how to use the ferts you bought, I also agree with Busteruk7, I never foliar feed, I do spay with nute-free water, but only when the lights are out, and only in during vegetive growth. Every drop of water on your plant acts as a magnifiing glass when your lights are on, that's probably one of the reason's leaf burn occured. Another reason could be your nutes. What product are you using? no matter what the product, I would start by soil watering plants at 1/2 or even 1/4 strength solution, and gradually work your way up to full strength.