By not watching TV yourself.
I watch station EWTN and TMC. Sometimes I watch History or Discovery depending on the show. The Weather Channel is not bad and an occasional sporting event.
It is just my wife and myself. Our grandkids are well trained by their parents to keep TV to a minimum.
We control our pleasures and our kids will have control also.
It starts with us.
"By not watching TV yourself."
Trust me, that DOES NOT work! I gave up TV for Lent (I wasn't really watching much anyway, so it wasn't too difficult) and my daughter still watches her "shows". Most of what she watches is Nick at Night and ABC Family Channel, etc.
I agree that we should set a good example, but that does not guarantee the results we desire. Monitoring the TV and setting a good example is the best we can do (and prayer!)
Regards