1. Do they publish my sort of book?
It may sound obvious but all agents report being sent work in genres they don't represent. Check them out first - look in a directory such as The Writer's Handbook, check out their website or research their clients.
2. Do I want editing?
Most agents will have worked at publishing companies before going over to the dark side. They will have either worked in editorial or rights, sales, marketing. A former editor may be unable to resist the urge to edit your work which, depending on your point of view, may be a good thing. On the other hand, you might prefer the sort of agent who settles down happily with a stack of miniscule-print contracts and enjoys quibbling over percentage points, in which case a background in rights would be good.
3. Big or small?
Do you want to be a big fish in a little pond? In which case you want a small agency. Your agent's income will be directly linked to yours, so they've got extra reason to sell your books (and generally be nice to you!). A big agency may make you feel they're too busy dealing with their star authors to have time for you. The number of authors each agent represents is also relevant - see also 6.
But a small agency may not have as much clout as a large agency, and are more likely to specialise. They won't have separate departments dealing with children's writing, television/film, journalism, non-fiction and so on. Neither will they have offices around the world. This doesn't have to be a deal breaker because smaller agencies usually have agreements with to bring in the expertise when needed, but if you know you want to write, for example, both adult and children's fiction, you need an agent who either does both, or is with an agency where there are separate departments - or is relaxed with you having multiple agents.
4. Could I have a business relationship with this person?
Call me pathetic but I was terrified of my acting agent, and top of my wish list when I started approaching agents was not to be frightened by my agent. Some literary agents I have met are scary... On the other hand, some relish the formidable qualities of their agent - my friend Jane Wenham Jones calls her agent The Fearsome One. I've met her, and she is, but Jane is made of sterner stuff than me.
Please note that the question was not Do we get on? Your agent may well become a friend but fundamentally it's about business.
5. How old are they?
Not an ageist question really. Young agents are enthusiastic and keen to make their mark, but they may not have either the contacts in publishing or the experience. On the other hand, they may be actively looking for clients. Older agents have shedloads of experience and contacts - and existing clients who need looking after so they're not actively looking for new clients. I've heard it said that you should look for a younger agent so your careers can develop alongside each other.
6. What about the money?
No reputable agent should ask you for money up front. Full stop. No choice to make here - if any agent suggests payment for reading fees or some such, run a mile.
But you may be bothered about commission. Don't be. The difference is likely to be small in reality. I'd prefer they took 15% or even 20% and got me a great deal rather than faff around with saving 5% and going with the agent who only wanted 10%. My agent told me she represented fewer clients, so she could give them more individual attention which was why she charged 15%.
Think about these areas before you start sending out or you'll end up like an author I know who had an offer from an agent, and then got cold feet about them. Don't waste your time or theirs and do your research right at the beginning of the process.
NEW!!! I've finally got round to organising some course dates....
How to WRITE a Novel: London 3rd May/Birmingham 7th May/
Oxford 8th May/Exeter 21st May/Bath 12th June
How to SELL a Novel: London 24th May/Exeter 4th June/
Bath 3rd July Details are on my website