Hanging Christmas lights on gutters can be tricky, but it's possible with the right tools and techniques. Here are some steps to follow: first, make sure your gutters are clean and clear of debris. Next, choose the right ladder or platform to reach the gutters safely. Then, use a ladder with rubberized feet to avoid damaging the gutters. Use a ladder stand-off to keep the ladder from leaning against the gutter and damaging it. Finally, use a ladder safety harness to keep you safe. Be sure to work slowly and carefully to avoid any accidents.