1. Don't ever accept an invitation to dine with Livia...but if it's mandatory, bring your own food & wine. 2. Don't touch the figs. 3. Having the lust of a dog in heat will leave you metaphorically screwed. 4. You can be older than your parents (or grandparents). 5. Always destroy your 'Murder the Emperor!' rough drafts. Do not leave them in the trash. 6. If you're made a successor, DON'T expect to live long. 7. Trust no one.
Don't invite Caligula to your wedding, or introduce him to your wife, or your daughter, or your son.
It's better to be laughed at than executed, your body thrown down the Weeping Stairs and torn apart by the rabble until there's only a trunk left, your skull carried off to the public baths and used as a ball.
If Livia invites you to dinner, just go ahead and slit your own throat.
Don't call the emperor's daughter fat to her face.
Don't believe someone when they say "there'll be no pain" especially when they are holding a dagger.
When you are emperor and you're in a tight political spot "find a dog who'll eat a dog".
Don't force your soldiers to say "give us a kiss" when they have to communicate with one another.
Don't allow yourself to be afflicted with that "infantile disorder known as republicanism".
Don't put anything important in writing.
Don't have public orgies if you want to keep your infidelity a secret.
Don't bother to have any sons if you are only a descendent of Augustus and not Livia.
Make sure you enjoy any and all dance performances by Caligula.
Don't let Antonia find out that you've been mistreating your children.
If you're emperor just do what Livia says. It'll be easier in the long run.
If you're a pretty noble woman and you have one or more extramarital sexual partners you WILL suffer an early death. (Julia, Livilla, Drusilla, Messalina, and in the book Agrippinilla.)