draw self portrait while look at multiple samples, see my study
http://bbs.wenxuecity.com/art/40442.html
To see things by comparison.
If you looked single work only, which is a "dead" image (in relation of living subject like looking at mirror), your time is not best used, like you eat over cooked, less nutrient food not raw food.
Also talk my writing in English, to stick on it is to best use our time, to exercise in a full load, and may readable by ABC and all others. Even awkward English is better than flawless Chinese, since one narrow his vision like a frog enjoys a well.
