Only the educated are free.
Always desire to learn something useful.
Do not weep do not wax indignant. Understand.
If you've got a talent, protect it.
Leap, and the net will appear.
Begin to be now what you will be hereafter.
The dog that trots about finds a bone.
The most effective way to do it, is to do it.
Well done is better than well said.
Be gentle to all and stern with yourself.
In hard-core science fiction in which characters are responding to a change in environment, caused by nature or the universe or technology, what readers want to see is how people cope, and so the character are present to cope, or fail to cope.