Professional temporary roofline lighting is typically installed with purpose-built clips selected for the roof edge, gutter or other appropriate attachment point. The goal is consistent bulb orientation and spacing without making the installation look improvised.
Every property is different, so roof material, edge conditions, height and safe access should be evaluated before deciding how a particular section will be installed.
Ideas & Advice
A clean roofline starts with the attachment method.
How professional temporary Christmas lighting is attached without relying on permanent fasteners in typical applications.