Verandah covering roof gutters. How do I clean?

[Citroënbender]

It's going to be a curly one to ever get perfect. A few points to consider.

Every bit of junk you clear out helps, it's not worth getting sucked into a vortex seeking a perfect result.

Make sure the downpipes are flowing freely all the way to the street or pit. Familiarise yourself with where they all come out.

If they are blocked this is called a "stormwater choke" and usually simple to clear by a plumber with water jetter. Sometimes if it's just a bit of leafy buildup you can flush it with a garden hose poked into the top of the downpipe.