Be extremely careful when conducting roofing jobs, and don't try to fix things too quickly, as it can result in getting a very serious injury. Always think through everything you need to do, and make a detailed plan. Never do anything on the roof if is wet or slippery due to water or ice; it is much safer to wait for the suitable weather.
Some other safety rules include wearing rubber sole shoes, using a harness and having somebody help with the roofing job. If you suspect a leak in the roof, use a garden hose to spray water on the roof, and examine the area for leaks. However, never use this method if the temperature outside is low enough for the water to freeze. Clean the gutters regularly to prevent leaking.
Another important part of roof care is making sure that dry rot doesn't appear. To do this, put in a ridge vent, and connect it to the soffit vent. Dry rot can cause parts of the roof to sag, which can result in the roof shingles becoming brittle, cracking and leaking. Make sure that the ice doesn't build up on the roof during winter by connecting a drip edge to the roof and installing rain and ice shields.
Some of the most common places where leaks appear are rubber roof boots. If they have dried up, buy replacement boots, and put them in place.