Avoid paradoxes. Seriously, don't even look at them. You'll only end up with more questions than answers.
Don't try to change historical events. You'll only mess with the space-time continuum... and the timeline... and your own sense of self.
When encountering a time-traveling companion, be cautious. They may be a future version of yourself, but that doesn't mean they won't try to kill you.
When experiencing time dilation, stay hydrated. You'll be stuck in a 20-minute loop for weeks.
When stuck in a time loop, try to find the exit. If that doesn't work, try to find a time-traveling companion who's not you.
Predestination Guide Time Traveler Ethics