When something is 'a shoo-in' it means it is certain to win or succeed.
Note: the pronunciation is the same, but the spelling different to a 'shoe', which is worn on the feet.
Rachel thought she'd be a shoo-in for a promotion within the company.
After such a successful role, the actor was a shoo-in for an award nomination.
He's a shoo-in to win the next election. He'll win easily.
Don't confuse it with
To be in someone else's shoes means to experience something from another's point of view.
If you were in her shoes, you wouldn't have gambled that money away.
It is believed the term 'a shoo-in' is derived from horse racing when, during a corrupt or 'fixed' race, a slower horse would be encouraged to finish ahead of the others.