Walking around roofs can be dangerous. Make sure you use a good gripping shoe that can grip into the shingles. But the most important thing is your ladder. Make sure you get the ladder safe and stable, dont take chances with an unstable ladder. Also dont just put it up so it barely reaches the roof, better to have 4 or 5 feet of ladder over the roof line. That makes it easy to get off and on. And certainly never attempt to get on a roof if you have been drinking any alcohol.