'To keep your eyes peeled' means to stay alert and look out for something or someone.
John told me he'd meet us in the mall. Just keep your eyes peeled.
We need to follow signs for the motorway, so keep your eyes peeled.
Mum will be home any minute. Keep your eyes peeled whilst I tidy up!
Don't confuse it with
'To keep your nose out' means to mind your own business.
This has got nothing to do with you. Keep your nose out!
A modern jack-o'-lantern is typically a carved pumpkin. It is associated chiefly with Halloween. The top is cut off, and the inside flesh then scooped out. An image, usually a monstrous face, is carved out, and the lid replaced. The name is associated with Irish folklore about 'Stingy Jack' who played tricks on the Devil.