Employ one agent.
Price realistically.
Look at the local property pages. Whose adverts stand out most? Phone around and ask about commission.
Get 3 EA 'valuations'. Don't believe twaddle. Make your mind up about what you'd sell for but don't tell the agent this yet! When they ask what you want, ask what THEY think it's worth! Look around other similar houses like yours that are on the market to get a feel for what your place may fetch. Ask agents' advice about what they'd advise you to do to sell your place- don't necessarily follow it but it's an indicator of what their 'eye' is like.
Ask how many photos you'll get on, say, Rightmove (that's where I think MOST buyers look!). Ask if they actively contact people who are looking for a property like yours. Ask how available THEY'LL be to show potential buyers around. Make it clear you're paying THEM to sell your house, not for YOU to conduct the inspections yourself!
Make sure they'll bring any offer to you however supposedly ridiculous.
Re the house, declutter, declutter, declutter. Have you got a garage? Put as much superfluous stuff in there you can (I put 1/4 of our excess furniture into a storage facility when I sold my house) and people expect to see cluttered garages! Get pictures off the walls and ornaments off surfaces, leaving one or two key pieces.
Keep the bathroom and kitchen spotless. Bribe the DCs to keep their rooms clean.
And good luck! If it's any consolation, the 3 houses we've looked at over the past 3 weeks have all gone under offer so there IS movement in the market out there at the right price!