It is useful to constantly observe, note, and consider.

When you are alone you are all your own.

As every divided kingdom falls, so every mind divided between many studies confounds and saps itself.

When you draw a nude, sketch the whole figure and nicely fit the members to it and to each other. Even though you may only finish one portion of the drawing, just make certain that all the parts hang together, so that the study will be useful to you in the future.

I am never weary of being useful... In serving others I cannot do enough. No labor is sufficient to tire me.

Let proportion be found not only in numbers and measures, but also in sounds, weights, times, and positions, and what ever force there is.

The painter who has no doubt about his own ability will attain very little.