firstly, do you have a specific Race you always go as?
for me personally I ALWAYS go as a Dark elf, if there is the option to, its always the dark elf.

and second, how do you decide what "Build" your going to do?
I was always terrible at this, when i say I'm going to go good, I go bad, when i wanna go bad, I go good, When I wanna go stealth, I go magic and so on, and so forth,
but typically I go, one handed+Archer, with a bit of Magic(Some destruction, some conjuration, restoration, and some enchanting) with a bit of stealth for sneaking, and lockpicking. of course,
I never go unarmed, 2handed, aliteration, mystisicm or any thing else i did not list, for some odd reason,