There is pretty much no way to know everything you need to know before you do it. It's not like I know everything, but it's amazing the difference between my first grow and the one I have going now... so much less stress because I kinda have an idea what to expect. I totally thought I was going to have a perfect first grow, and now I see that the first goal is to have a problem free grow... from that you can build to perfection.
But all that being said, my bud from my first grow is sooooo good. I can't imagine what I am going to grow in a few years when I have things down a little more.
It is funny when people think there is nothing to it. Sure the plant will stay alive, but to get good stuff you have to work.