Wherever you are - be all there.
To know oneself, one should assert oneself.
Either you run the day or the day runs you.
It's always too early to quit.
Well done is better than well said.
Always desire to learn something useful.
By failing to prepare, you are preparing to fail.
Without hard work, nothing grows but weeds.
Things do not happen. Things are made to happen.
The secret of getting ahead is getting started.
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.