I would suggest getting the Solos for the Double Bass Player, compiled by Oscar Zimmerman. There are a lot of transcriptions of classical pieces for bass, plus a few Bottesini pieces and a few others (I can't seem to find mine at the moment...). This is a really good book for beginners, IMO, as it has some pretty simple pieces moving progressively into harder literature. You might also get The Elephant from Saint-Saens' Carnival of the Animals. I can't remember if you play bass guitar too, but if you do, these pieces will probably be a good starting place. If you are completely new to bass, maybe someone else will have some other suggestions. Do you have a teacher yet? They'll definitely be able to tell you what to work on. Good luck!