I primarily use layering method and it takes me several layers to accomplish a finished painting. Each layering is done in one of the mentioned watercolor techniques.
Wet on wet: This technique partially absorbs the paint into the paper causing the paint to move less when water is applied in subsequent layers. This keeps colors relatively fresh on paper as they don’t move easily and mix with others. But this also makes paint look less vibrant as it is partially absorbed into the paper which is why I switch to wet on dry after initial few layering in wet on wet.
Wet on dry/glazing: This technique keeps the paint on the surface and as a result gives vibrant look. I do not switch back to wet on wet once I start to use this technique to avoid disturbing underneath glazes.
Dry brushing: It is more like airbrushing. Excellent for textures and darkening of shadows.
I begin with wet on wet technique and use this for few layers until I reach certain tone and saturation in color. I then switch on to wet on dry technique/glazing on certain sections to make the colors look more vibrant and finish with dry brushing at places for textures.