I've only taken 5 deer in my hunting career so far, so take anything I say with a grain of salt in reflection of less experience than many.
In general, you will be most likely to find deer moving and in the open near dawn and dusk. In most cases, they will tend to be hunkered down in thick cover during the day. Still hunting game trails, especially along the edges of open feeding areas (grass or crops) is a good bet at the beginning and end of the day.
Lots of guys don't bother trying to hunt during the day at all, but unless you've seen observed evidence of the local deer in a certain area during the day, I would be following game trails towards the thickest cover I can find during daylight hours. Keep in mind this is incredibly difficult because the deer can be very alert while in cover, and its almost impossible to move through that cover silently. But hunting and getting skunked is still better than no hunting at all
Some groups of hunters will try to hunt during the day in groups by identifying areas where the deer are likely bedded, then posting some shooters around the spot and having a few guys walk though it trying to flush them out. But of course, that takes a group, and is not everyone's preferred hunting style.
Remember that scouting is your best friend, even just driving around will give you an idea of what fields/areas the deer frequent, then you can try to go after them on foot the next day, for example.
Good luck!
Red