The last few that I have found have been laying on trails, however, I have seen as recently as last week bucks at my dad's house butting heads. So I am sure that would translate into sparring knocking loose antlers off also.

As for looking for sheds:
go slow
take your time
walk the trails
take a pair of binoculars with (if you have some)
take frequent breaks and look around
investigate everything (I have found sheds frozen below the surface of puddles)
stop and look at where you just came from (it is possible to kick one up without seeing it)
dont forget to look at your feet besides looking in the distance

if you have access to a older shed, small, large, whatever, take it with you and throw it around, so you can see what you are looking for, helps train the eye, I will still take sheds that I have just found and toss them ahead of me.

It is actually pretty easy to find them, if they are there to be found......

If you know where the deer are, and it is easy to get to, check the area as often as you can, or as much as you feel comfortable with.

One area that I have been working over pretty hard, I noticed that the sign (tracks/beds) was getting less, so after staying out of the area for a couple weeks, came back and the sign is thick as ever and we found 3 sheds no more than 60 yards apart.