The mind is governed by laws of association, such as the law that
ideas which enter the mind at the same time emerge at the same
time, one assisting in recalling the others.

The reason why people cannot remember what they want to is that
they have not concentrated their minds sufficiently on their
purpose at the moment when it was formed.

You can train yourself to remember in this way by the
concentration of the attention on your purpose, in accordance
with the laws of association.

When once you form this habit, the attention is easily centered
and the memory easily trained. Then your memory, instead of
failing you at crucial moments, becomes a valuable asset in your
every-day work.

Exercise in Memory Concentration. Select some picture; put it on
a table and then look at it for two minutes. Concentrate your
attention on this picture, observe every detail; then shut your
eyes and see how much you can recall about it. Think of what the
picture represents; whether it is a good subject; whether it
looks natural. Think of objects in foreground, middle ground,
background; of details of color and form. Now open your eyes and
hold yourself rigidly to the correction of each and every
mistake. Close eyes again and notice how much more accurate your
picture is. Practice until your mental image corresponds in every
particular to the original.