The key to safe and well-mannered driving in the country is patience. You must accept that the pace of life - and driving - in the country is slow and relaxed, and leave your city techniques behind.
When roads are narrow and visibility is poor, you will find any number of hazards - from herds of livestock to groups of hikers. Accept that country driving is slow, so take your time and enjoy the scenery.
Keep to your side of the road, and don't let reduced visibility tempt you into wandering into the oncoming lane.
Be patient: you may be stuck behind slow-moving tractors or agricultural machinery, but this will rarely be over long distances. Just resign yourself to moving slowly, and resist the temptation to flash your headlights or swing out from behind.
Be very cautious around horses. If you see a horse and rider ahead, slow down to a crawl and creep behind. When it is completely safe to overtake, pull out, giving the horse a wide berth and drive very slowly. Never accelerate hard or use your horn.
Keep an eye open for pedestrians. Walking down country lanes can be hazardous, and where there are no verges pedestrians are often forced to walk in the road. Slow down if you see a pedestrian ahead, and overtake gently. Aggressively racing past with just a hair breadth's clearance is the height of bad manners.