Stats look pretty much optimal.
Max set traps asap. In other basic abilities, specialize according to your party composition.
Dual wielding definitely. Best off-hand weapons are those which offer +1 attack to your main hand (there´s one short sword and one scimitar which do that). Since short swords are useful for thieves in general (backstabbing), putting a point in them should be a must. Other good main hand choices are long swords and there´s also a nifty overpowered katana. Put a point in short bows for backup (the one which offers additional attacks per round is the best).
If you become bored with the class, you may try to dual class it to mage (level 11 is the best, you´d have to play a human for that), but be aware that single class thieves really come into their own at higher levels due to their diverse HLA selection and, in the case of bounty hunters, also maze traps.
Anyway, if you don´t mind being spoiled a bit, there´s a comprehensive thief guide here:
http://www.gamefaqs.com/pc/470765-baldurs-gate-ii-throne-of-bhaal/faqs/27550
Also, if you plan to play with mods, check out Rogue Rebalancing. It´s an all around well thought out one, adds more distinction to the classes and contains a great thief-flavored encounter:
http://www.shsforums.net/forum/79-rogue-rebalancing/