You gotta get out in the woods and walk around. You're looking for thick areas that provide a lot of cover and security for the deer. The thicker the better. If you see a trail going into a group of briar bushes and think to yourself "there's no way in hell I'm walking into that stuff." that's what you're looking for. You should be able to identify beds and look for abundance of other sign like rubs, scrapes, etc.