I'm also a bicycle commuter whose feet tend to sweat a fair amount, especially when I'm active. This caused both strong foot odor and recurring athlete's foot.
What's worked best for me:
- Shoes with plenty of ventilation.
- Merino wool socks.
Shoes have typically been "running" sneakers which have synthetic leather with plenty of mesh bits, and some retroreflective detailing. I haven't tried too many varieties, though. I know on days I wear something else, I can feel the heat and moisture difference.
The wool socks made the biggest difference. They don't stop the sweating, but they're breathable, wick moisture away, and don't feel wet when they get moist. Mostly I've been using short SmartWool cycling or running socks, but in colder weather I'll wear taller socks from them. SmartWool makes both "light" and "ultra light" athletic socks. The "light" are thicker on the sole than on the top, and generally worked best for me. The "ultralight" are less comfortable, tend to bunch a bit, have proportionally less wool, and just generally aren't as nice to wear.
Merino is the least itchy wool around, so other types of wool are likely to work less well. Avoid acrylic, it looks like wool but doesn't work the same.
After discovering merino wool socks, I will never go back to cotton. At least not if I'm doing anything vigorous.
The downside: merino wool socks are expensive. One good pair costs as much as a whole pack of basic cotton socks. Maybe just get one pair and see if you like them, first.
Other things worth trying:
- Don't wear the same shoes two days in a row. Alternate between two pairs. That makes sure they're totally dry when you put them on in the morning.
- Bring a spare pair of socks. Either swap them mid-day, or have a pair to wear during your ride and a pair to wear at work.
- Foot powder (or something like baby powder that's the same stuff). Typically this is talcum powder or corn starch based. Specifically made for keeping feet dry.