how to say "don'ts" to kids?

Kids are full of miracles and surprises! They are innocent, cute and mostly unpredictable in their actions…J They may suddenly cry hard or laugh happily for simple things…but they are always entertaining and amusing. Really!
In their first years or we called it the golden ages, they absorb and learn everything around their life; actions, languages, music, etc with quite fast or even faster and stronger than what we ever think. Just to take an example; my little boy who is still 3,5 years old, has memorized most of today’s single hits and some advertisements on television show which –I think- is not really good for him….wups, how come?? This only one example how the electronic media comes with negative effects on our children. And honestly, I have a big task on handling it now….(share me if u don’t mind….!) But some friends of mine say that it doesn’t mean negative “at all”---> they say, “if your boy has musical attractiveness, means that he has a good emotional control, cos his left brain works as it should be, so no more worries, just guide and do a balance such as introducing them good songs which is more suitable to their ages” Ooooh, hope so! ! And I see that he could recite and memorize some short surah of Al-Qur’an as well as he sings those songs…hhmmm…oh my!! J
Psychologists say,” try not to say “don’ts” to kids, and just let them grow as they are, exploring their surroundings naturally” ……it’s not easy, oh yes, because parents specially moms (who are enough tired doing home-things) sometimes have no more patience and time to say “please….” (language of guiding) to their kids. And “don’ts” is practically easy to avoid them doing negative or danger actions as well….(it happen to me anyway!...:p)
How hard and how difficult it could be, but educating our children is a great responsible in our life….let’s just give them our best, then we would never regret…