I am a very big fan of 10 power and Swarovski are the best, they are a hell of an investment but if you are serious about the sport they are simply that. an investment
think of them as being more important than your rifle or bow. How you harvest them doesn't matter if you can't find them.
I will say that I bought my daughter a pair of 10 power Vortex's this year and they are really good glasses.
Having something to rest them on, having a bio harness, and being comfortable make all of the difference in the world.
I think there is something to the post about training your brain, I grew up in NE Washington and it was a game whenever we went somewhere I would see how many deer i could spot on a drive. I still do the something to this day with my kids. Yesterday I saw a big buck about 50 yards off the side of the Sepulveda pass at 330 PM.
As far as how long do you spend glassing an area I would say it depends on what you know about the area. I have spent an entire day in 1 spot and I have spent a few hours at certain times of day at another. I have a piece of property up in Coalinga and we have a spot that is like a deer highway. We have made the spot we glass from very comfortable and we have taken a lot of deer from there. I sat there from an hour before daylight until noon on the last day of the season last year I saw quite a few deer and a couple of decent bucks, just not what I was looking for. I needed to be on the road by 2 PM. I got up from my position at noon to stretch and gather my stuff. I was making quite a bit of noise, when I climbed off of the rocks a nice 4x3 jumped up from under where I was sitting. He was no more than 15 yards below me and I either never saw him come in or he had been there the whole day. and other deer had walked right passed where he was. I did not attempt a shot because he was moving at a good clip. my cousin got him that evening. and he got up from the same spot about 30 minutes before dark. somehow that buck slipped back in there in the hour that nobody was sitting there.
sometimes you can stare at a spot that you just have a gut feeling about and see an ear twitch, or a hot shine a bit
you won't see that in a cursory scan...
If you know the area, get as comfy as possible. get as well hidden as possible, and stay put as long as possible. its amazing how much deer move throughout the day.
If the wind shifts and I am in a bad spot. I give up and get out before I ruin a spot though. Take your time and you will be successful. If you get impatient, take the book with you. I have done that to give my eyes a rest from glassing, bring snacks. stay well hidden and remember, if you see a deer and they are not looking at you, you are doing it right... If everything you see is staring at you, they have known you were there for a long time....