Lessons it took me a few cycles to learn

-lay tarps on the floor before doing anything
-don't grow your mothers so big they can't fit in the car
-Yankees suck
-back up your genetics with a friend if you can do it safely

Things I have learned or learned through other's mistakes

when watering/feeding use about 1 gallon of water per gallon of soil. Using more water reduces the chances of yukky build-ups in your soil causing ph problems and lock outs.
The use of a dehumidifier and A/C especially in a smaller growing environment is key.
slowly increase your nutes and DO NOT use ANY until you have grown about 4-6 sets of leaves on your seedling.
Slacking on your PHing will cause more time in damage control than it would have to make sure it was right in the first place.
Humidity levels during flowering need to be as close to 50% as possible. Otherwise you will have un-smokable moldy weed
Temps in your grow room over 85-up (should be about 70-75 degrees with lights on) are killing your plants.
If in a small grow space (small closet) if you spend a lot of time in there, they are probably getting enough CO2 from you breathing on them. ( I spend a lot of time with them)
Dry ice is another good source of CO2 in a small closet grow

MOST IMPORTANTLY:

LISTEN TO YOUR PLANTS! Really pay attention to them. They will tell you what they need. If you wait until the problems are way out of hand, you caused more damage to them in the long run and it will cause you a lot of headache in the end.
Good luck and happy growing.

Don't tell anyone about your hobby

Don't show anyone your garden

Don't charge $1000 to your credit card @ the local hydro shop.

Don't date mean / vindictive members of the opposite sex, then break-up.

Don't eat yellow snow

PH should always be checked and maintained in range :cool:

It's better to give them little less nutrients than little more ;)

Use C02 it's worth it :D

Take care of the smell !! :wtf:

Flush , FLush , Flush !
Harvest when it's time , buy a microscope. :D

Take really good care of your drying , all the hard work can go the drain if you don't dry it good.

:rasta:

Im still a total newb but I have learned...

Buy a good book on growing AND READ THE SHIT OUT OF IT.

learn what stresses out a plant and avoid it

don't wait for a male to splooge all over your girls before removing it (pre-mature epollination)

consider the time it will take to finish the grow before you start (do you have a trip comming up?)

Check your timers to make sure they are on auto and did not accidentally get put onto "on" anytime you move things around the room. Those little timers get put onto a different mode quite easily if your tiny little fingers come anywhere near the program button!!!!