You need to do the following:
See a chirpodist once every 6 weeks.
Wear leather shoes, with leather linings if possible. Plastic shoes are cheap and will last forever but they will destroy your feet, leather is less hard wearing and costs more but offers you comfort
take a change of socks and shoes to work every day and change them in your break.
Wear full leather insoles in all your shoes with charcole layers to absorb moisture and keep your feet comfortable.
Make sure you get off your feet for at least 15 minutes of each break, more if possible.