Tips on pressure-washing my vinyl siding, please??

Slow and steady. Work in a pattern so you wash all the dirt off evenly.

Watch the pressure. Too much and you can blow right thru the siding.

Start high and work down. Not too much pressure. podssibly start with the soap at the top and switch to regular water working down.

If you can afford to, hire it done by someone who is familiar with their equipment. If that isn't possible, rent the equipment and start on the back of the house where you can experiment a bit. Ask for instructions and hints where you rent the equipment. Always wear eye protection.

take time and don't use so much pressure.

Kinda expensive but Wet and Forget