Understanding SEM on a deeper level

I recently began a new job working in paid search for a large retailer.  In 10 days I've learned a LOT.  My career has been rooted in client-service so this role is new for me on a couple of levels.  My world has been opened to a level of analytics and "turning data into knowledge".

Example:  I've learned to measure positive and negative ROI metrics, then use those numbers to craft a story and strategic recommendations which need to be pitched to internal business managers.  The numbers are specific and always questioned, so it's important to bring your A game.

Additionally we are changing our SEM agency and I've been able to participate in a number of conversations on the best way to set up our new campaigns which has given me a new appreciation for the level of knowledge and expertise that these folks offer.

What lessons will this week bring?