Check out this blog, that of a literary agent based in San Francisco: Nathan Bransford
On the panel on the right are many questions and answers on finding an agent, submitting a query letter to agents, and Nathan's Ten Commandments For the Happy Writer, which is refreshingly down to earth. Bear in mind though, that much of his advice is applicable to the U.S. market. And bear in mind, too/two, my golden rule about all things writerly: There Are No Golden Rules. So take it all with a pinch of salt and enjoy.