Among the homophones, the one I see most often (beside there, they're and their and your and you're) with repeated mistakes in manuscripts involves the words reign and rein. These seem to get mistaken in common expressions.
Reign- is the time of rule of a king, queen or other ruler. Dominating power or influence.
Rein- are the strips of leather used to guide a horse. Used when talking about getting control.
(Also their easy to follow twin Rain- is water falling from the sky.)
On to the common expressions.
Let chaos reign. Verb. Meaning to let it rule. Let it be in charge. Dominate.
The reign of Queen Elizabeth the second is long. Noun. Time of rule.
Take the reins and drive. Noun. Meaning to steer. To guide. As reins are used in guiding a horse.
Rein in your troubles and smile. Verb. Meaning to control.
Now your turn. Which ones are right?
I hope the sun's rein is long and glorious today.
Rein in your awkward tendencies.
It shall rain on your parade.
It happened during the reign of my father.
Reign up your horse and stop for the night.
Did you spot the mistakes? The first and last sentence are wrong.
Hope this helps clear up some common mistakes with reign and rein.