People forget about "image" too.
Even if you don't tell anyone, if you have traffic at odd hours, parties, criminal history, neighbor complaints, and just being young and dumb will draw the eye to you.
Keep your yard looking good, try to keep a regular schedule regarding yourself and when company comes over. no new faces. or better yet live like a hermit like myself LOL.
Don't sport clothes that show your a stoner too much. Keep the tie dyes for special events. Look like a regular joe schmoe living your life will help as well. Keep your neighbors at a safe distance...don't be too friendly, but be nice polite and helpful. They'll keep an eye out for ya too without even knowing your up to anything
Live under the radar. Don't give em an excuse to put an eye on ya.
edit:
One thing that has kept me out of trouble is be very picky who your friends are. none of mine have any serious criminal offenses and 0 within the past 7 yrs simple possession being the worst. Most of my friends have micros or sumit in the garden. They are proffesional working people with families and just as paranoid as me
...its all the good weed we grow LOL. NONE of my friends deal. NOT A ONE. Watch out for the ones that get into trouble a lot...sorry they me be fun to be around get your back n all, but the first things cops notice are the people associated with those types. I call people like that an unnecessary risk. They will get you into trouble at some point. even if by accident. people like that i consider a time bomb..."oh crap, whats it going to be next"