Here's what will get you busted (no particular order):
1) Significant others - Got a girlfriend/friend/roommate/sibling/etc. living with you? Don't grow. Drama gets people busted all the time.
2) "Business" Partners - Sounds like a good idea at first, splitting costs, care taking, etc, it isn't. If your business partner goes down, so will you. You are effectively doubling your odds of getting caught.
3) Odor - Pot smells, and alot of pot smells.. alot. Deal with it, be prepared to pay dearly for it. One of the most expensive aspects of a proper grow room/area is neutralization and ventilation.
4) Intoxication - Don't get wasted at your grow spot, don't allow others to get wasted at your grow spot.
5) Appropriate grow spot - Don't grow in an apartment. Period. I know, I know, all kinds of people get away with. They won't get away with it forever, it's risky, don't do it. Don't grow near schools, churches, police stations, etc. If your carbon filters or vent system breaks down you'll want a good 200 foot buffer zone between your grow op and the homes/businesses of people who may or may not be sympathetic to the cause.
6) Appropriate power consumption - 1000 watts per bedroom in your house, anything more and you risk unwanted attention.
7) Drug sales - Don't do them from your grow op.
Faulty wiring - Don't cut corners, if your op catches fire you'll probably get busted. Buy a book, take a class, whatever it takes to learn how to keep your shit safe.
9) Follow the law to the letter - If you're growing copious amounts of ganja, the last thing you need is a cop banging on your door because of a bounced check, expired vehicle tags, unpaid tickets etc.
10) Light leaks - You should be able to completely close off your grow area and have no light shining through cracks, windows, etc.
11) Listen to your instincts - If you feel like you're being watched, or you get the slightest hint shit is about to go down, ditch your plants (install a disposal in your sink just for this purpose). It sounds pretty extreme, but look at it this way, if you're wrong you've lost a couple months of your time and effort. If you're right, you just saved yourself from years in prison, those are years that you can never get back. A couple of months of grow time pales in comparison to years of jail time.
12) Keep to yourself - Don't brag, don't show off, even after you've harvested, just play dumb about your source. It's in your best interest to keep it a secret.
13) Pay cash for supplies, don't get alot of them at one time, don't order them to be delivered to your grow op. Personally I avoid hydro stores, it's up to you if you trust the proprietors or not.
Something I do, but not many others will suggest; I rarely get high when I'm growing, the paranoia tends to be a bit much for me. It's easier to keep a level head and minimize foolish mistakes when you're not blazed 24/7.
Eh, I'll add more if I think of them.
