As you get better at it, you might start to have problems with your foot slipping off the pedal. Most of us use the unintuitively named clipless
[1] pedals - where a cleat on the shoe clips into a binding on the pedal. This makes spinning fast *massively* easier, and means you don't have to maintain a constant downward force on the pedal to keep your foot in place (indeed, you can even pull upwards on the return half of the cycle).
Of course, it's not all simple. Your foot being attached to the pedal can be a bit of a problem when you stop or need to get a foot down in a hurry on a slippery surface. With practice the release motion becomes automatic, but everyone finds themselves in an undignified heap at the traffic lights in front of a group of schoolkids or an attractive MOTAS (or in a bed of nettles, if off-road) at least once.
However, you can still get a lot of the benefit with partial toe-clips like these:
They won't allow you to pull upwards like clipless pedals, but they will stop your foot sliding forwards off the pedal, without any clever release technique, and they'll work in any kind of shoes. Recommended.
[1] A reference to the older solution of clips and straps, which are even more fiddly to use.