What do you think parents should do when children do something wrong such as telling lies?

It depends.
Sometimes children lie because they enjoy the imagination that they fancy for themselves and haven't realized what they said is totally fake or lies for others.
Some children do tell lies on purpose,though.Some for fun,others for some hard-to-say reason.
I guess as a parent,you should firstly trust your own kid and find the "why" behind his lie before blaming anybody or anything.'Cause anyway,it is you who raise him up,right?.