How to set Profit targets

I searched a bit and couldn't find material on how to set profit targets and its significance, is it really necessary to set profit targets and if yes, what are the different ways to do so?

bro its not definite ,it depends on you, that how much the stock will run on your time span ,and also u can see the possible resistance and set the resistance as a target.also there r technical patterns . so by measuring them u can set the targets....correct me senior guys if im wrong as im still learning ta.

Thanks Bunti, I was thinking that there must be a direct and definite way of setting profit targets like the methods used to set stops..