Also a change of socks can help prevent blister formation. Carry some petroleum jelly and add it liberally to any areas that may be chafing. Common chafing areas to keep an eye on are between the thighs and under the arm pits. Good comfortable clothing will also help prevent chafing problems. Lastly good prevention of injuries and general aches and pains comes from a good exercise program.
Some cross training is always beneficial.
Try some jogging or bike riding for something that is aerobic but different to hiking. This is good for keeping the muscles long and the joints supple. Too much repetitive work tends to shorten the muscles and reduce your flexibility, increasing the chances of injury. Also some upper body weight training and abdominal exercises can be useful. This will help you keep your body upright and in the correct posture, relieving the back from too much strain.