You've polished your manuscript as best you can, maybe even had it professionally critiqued several times; you've considered the market and your hook, what makes your story unique; you've done your research and submitted to the appropriate agents. It's only a matter of time before the phone rings.
I've included several links below so you can be prepared for that glorious phone call!
The first link is written by Cynthea Liu.
This link is a treasure trove of agents, who they work for and what they represent.
Bonus link: This link, written by Tracy Marchini, tells you what not to say to an agent during a face to face critique and what not to write in your query letter. This information it transferable to an agent phone call.
Good luck and best wishes!