Tools worth having
A sturdy extension ladder, a ladder stabilizer that spans the gutter, plastic gutter or shingle clips, tile clips for tile roofs, outdoor extension cords, a timer, zip ties, and a bag that hangs from your belt so both hands stay free. Skip the staple gun and the hammer entirely.
Test every strand on the ground first so you are not troubleshooting on a ladder.
Plan the run
Walk the house and decide where the lights go, where the power comes from, and how many outlets you will need. Measure the eave lengths and buy strands to suit. Decide whether you are outlining the roof edge, the gables, or both, because the clip type changes for each.
Fewer, longer runs mean fewer connections in the weather.
Clipping to shingle roofs
Shingle clips slide under the bottom edge of the first course or hook onto the gutter lip. They hold the strand along the eave without any fastener through the roofing. Never staple or nail through a shingle; each hole is a future leak and the sun will open it up within a year.
For gable edges, use clips that grip the rake trim rather than the shingles.
Clipping to tile roofs
Tile clips hook under the bottom edge of the eave tile or over the top of it and hold the strand without lifting or drilling. Do not walk on the tile to reach higher runs; work from the ladder and use a pole for the last bit. If a strand will not reach from the ladder, it goes somewhere else.
Broken eave tiles in January are the most common light-related repair I do.
Taking them down
Do it in dry daylight, unclip rather than pull, and coil the strands as you go so next year's job starts with working lights. Check the eave for any clip you missed; a forgotten clip can trap debris and hold water against the fascia through the winter.
If you find a cracked tile or a torn shingle during takedown, that is the moment to book a repair, not spring.
Before you start
Check the weather for the day and the night before; dew on tile in the early morning is as slick as rain. Tell someone you are going up. Clear the ground under the ladder of hoses, toys and pots. Then work slowly; the display will look the same whether it took an hour or three, and the hospital is a long way from festive.