If you are not sure what to do, ideally is call a professional or you can do it yourself. Obviously you need good power washer and at least one set of quality ladders.
Best what you can do is walk around the house and check for what needs to be done. Usually footpaths are first on the list that become dirty and slippery to walk on.
Very important is check gutters all around the house, and make sure they are all in good condition. Clogged gutters may cause bigger damage to your house than you can even imagine. So make sure they are cleaned regularly twice a year.
Soffit and fascia become very dirty after winter very easily, especially when your house is located near trees or near by coast. This is very important to keep clean and not only for esthetic reason but also for hygienic reason.
Walls of your house are same important like everything else. Nobody wants dirty walls covered with moss and other dirt.
Make sure to organise cleaning of your house before it gets too bad and will cause more damage than you can even imagine.