Dry or fissured feet could be due to dry weather, extremely dry skin, eczema, psoriasis
due to some other cause.
To keep the feet well hydrated, dip feet in warm water and use a pumice stone mildly( do not use vigourously as might cause erosions). Apply cream containing urea and lactic acid twice to thrice in a day and wear cotton socks. Apply a steroid and salicylic acid
based ointment in night daily. If possible consult a dermatologist
too so that underlying cause can be ruled out.
Hope that helps.