Leave your dog at home. Treat them with respect. Walk confidently. Arm yourself: find a big stick, or wield an umbrella. Always walk round the edge of fields and know where you're going to go in case they charge (into bushes, behind a tree, over a wall.) Remember they are prey animals, so if you carry something, like a coat, a map or book which you can open up suddenly to make yourself look bigger and more threatening they always back off.