My first Grow Setup. I need pointers for when I upgrade.

Hi, I just built my first grow cabinet. I used a 400w MH bulb with a Xtrasun reflector. A 400w MH/HPS electric Lumatek Ballast. I built a 62"x45"x22" cabinet out of 1/2" wood. I went to the opening of a new Hydroponics store down the street and got loaded up with swag I'm gonna use like free floraNovaGrow and Bloom. Anyways this site was the most useful tool when learning about cultivating. So i thought i would update the site with my personal experience. I need to keep learning if I'm ever gonna be a master. So if you have any ideas of ways I can improve my growing, please leave a post.

Oh yeah I'm definitely going to need to make a charcoal scrubber or something to take the smell down. My girlfriend's pet peeve. seeing as I have a open top that might be difficult. I'm planning on building some sort of top but I'm worried about overheating. Any help would be appreciated.