You'll need to correct the behaviour you don't want from Day One.
Say a firm 'No!' when he goes for your shod feet. Offer him a 'legal' alternative and when he takes it, praise him.

I insisted that our foster pup sit on the mat while I put on my shoes/socks before we went out, so she practised this solemnly with me all the time.
However, her Dogpa let her play with his shoes and she'd pull his shoelaces and socks, making his whole procedure fraught with little scoldings - this went on till she was almost a year old (but only with him!).