Kind of like this

the answer is in that picture actually
however, where ron phearlman wears it very well, ron phearlman is also in his 40's
what i'm trying to say is that this particular combo of facial hair and hair style (depending on how "young" your face looks) MAY make you look more mature than you actually are
but like i said feel free to experiment with some sort of facial gruff and take it from there
where definate moustaches, beards and goatees can be hit or miss, some facial gruff/five o'clock shadow always looks cool