I started a new character on skyrim and thought hey you know what I am going to try and use the bow only... But it came to my attention that I can easily get my killed by the trolls on my way to high hrothgar... I was wondering if someone could give me tips on this aswell as tell me if it is a mistake to just focus attention on bows... also are there any upgrade trees that I should focus on with the thief?

Maybe poisons/alchemy as well as sneak.

PS: Welcome to the forums There is actually a http://www.gamesas.com/forum/117-v-skyrim/section that this thread might fit better than the generalized "Elder Scrolls Series" section.