I made a number of ads for the brands I worked on. More than making, I reviewed a number of old ads of these brands as well as those of competition. Know quite a bit about ads made by my colleagues for the brands they handled and also those of their competition.
Big learning from all this, getting to insights is real difficult. You can toil for months to arrive at that perfect concept built on top of that perfect insight. But one thing is a given, the best insights translate into the best ads (even if the agency translating it into a piece of communication is bad) and hence resultant the ads stay in your mind for days and sometimes years.
