We're in the process of selling and buying.
The important thing with property is to get posted in the property portals, primarily RightMove, and a few of the others such as Zoopla and On the Market.
I'm not aware of a way to get on them unless you are with an agent of some sort.
I would avoid the run of the mill high street agents. They have a flair for selling easy to sell stuff and tend to loose interest in stuff that is more obscure. If you can find an agent who specialises more in what you have, they will probably come with the passion and the expertise that you need.
I would steer well clear of the likes of Purple Bricks. On line agents such as these basically only provide you with a way in to the property portals mentioned above and have very little knowledge of local areas or specialist properties. You are basically left to then get on with it. Furthermore, real estate agents hate dealing with online agents and you may struggle to buy a property if your agent is online only.
Time will tell with our sale - our agent is distinctly average and their associated conveyancing arm seems to be snail paced. Our property (detached and in a town), now sold STCC, was initially over priced (by them) and didn't shift and they seemed to be loosing interest until we suggested they remarketed it at a lower price.
The place that we are buying, in the country and with some land, has been marketed by an agent specialising in equestrian and country homes. Yes, they flatter a buyer, but the whole approach seems so much better and the standard of marketing is in a different league.