Because I was asked this by a friend and the email turned out to be, basically, a blog post...

Not exact, but a good start on the path if you are Jon Snow and know nothing.

When searching for an agent, do the following:
1. Search:
www.agentquery.com
www.1000literaryagents.com

2. Look for the exact kind of agent you want:
MG, YA, SFF, Fantasy, Romance, etc...

3. Look to see if they are open for submissions.
- Should say on their profile

4. Go to their agency website:
- Make /sure/ they are open for submissions (most up-to-date, hopefully)
- Make /sure/ you understand what their sub guidelines are (IE: first 10 pages, first 3 chapters, etc...)

5. Make some decisions:
- Sub to one agent and wait?
- Sub to multiple agents?
(IE: are simultaneous subs allowed? or is it exclusive?)

6. Submit your query (whatever the guidelines say)
- Follow the guidelines to the letter

7. Wait.
- This is the hardest step.
- Write something else while you wait.

8. When you get an answer either:
- Rejection: mourn, repeat the process
- Acceptance: panic, follow what the agent is asking for in a timely manner

9. Wait.
- Again, the hardest step.
- Seriously, write something else while you wait.

10. Final answer:
- Rejection, mourn, begin again
- Offer of Representation: panic, realize the agent works for you, have questions ready. If you don't know what questions to ask, consult author friends and social media.

Good luck!
Jenn