As an interesting quirk, you could consider taking the Cosmopolitain or Educated feat and study Architechure and Engineering. That should help you anticipate where a trap might be located or how it could work. Knowing if something is a load bearing wall could also be very important at times.
I'm pretty sure that Waterdeep gets Cosmopolitain, not so sure about Educated.
Plan to multiclass with four levels of fighter somewhere in your career. It will really help with the combat potential of your character, and you can make up the skill points in your core competencies later.
What sort of weapon do you favor? Dagger, Shortsword and Rapier all have their advantages, you should know which you want to specialize in.
Dagger can be thrown. That can allow you to get a full attack off on someone who is running past, which with Sneak Attack can be a huge difference.
Shortswords are usually considered more common than rapiers. You can also use a short sword in each hand since they are light weapons for humans. That would allow you to buy Weapon Focus and get the bonus on both weapons.
Rapier has the best critical range of the available weapons. Unfortunately, you can't use two rapiers (one in each hand).
Have to look at the regional feats for Waterdeep, see what is available. There might be something else that would help you more.