I would recommend you take time to give yourself regular pedicures. Invest in a decent pumice file and foot cream and then do the following once a week:-
1. Place a large bowl of soapy water on a towel on the floor. Using the pumice/file, work on the dry areas of your feet. Soak your feet for a few minutes.
2. Gently file the dry areas some more. Soak feet again.
3. Clip toe nails and file as appropriate. (each time you're working on one foot, always soak the other).
4. Apply foot cream and massage into feet for about 2 minutes on each foot. Leave to soak in for a couple of minute then wear socks.
You won't need to clip your toenails once a week but you should aim to soak your feet as it softens them up nicely. Do it throughout Summer if you're planning on wearing open sandals and the like. Come Winter your feet will be amazing!
Also, when applying nail varnish to toes you may get bits of varnish on the surrounding skin. Don't panic though, as a long soak in a bath the next night will wash those away and your nails will look perfect.
Do away with bad-fitting shoes though, Alix, if only to prevent longterm damage to your feet.