Getup

Interestingly, our getup also matters. In fact, in experiments, younger people tend to choose light colors and older choose darker. Flashy clothes also indicate childness. Even our hairstyle makes us look irresponsible. It's human psychology to judge someone based on their getup. 

So in this regard, one can wear something a little bit formal (not too much formal or too casual; a little above) and at least get a haircut that doesn't block their forehead like an emo kid.