I do a 'German' type one as follows:

Boil approx 8 waxy potatoes (don't overcook), cool then cut into slices or quarters.
Hard boil approx 3 - 4 eggs. Slice/chop up
Chop approx 4-5 spring onions
Mayonaise to your desire (I use whole egg mayo)
Salt and pepper to taste

Mix altogether adding enough mayo to 'coat' ingredients.
You can refrigerate before serving and this can keep for a couple of days.