To me, hunting smarter is all about making the best use of your resources to accomplish whatever your goal is. Your resources include your knowledge, time, money, strength, land to hunt, hunting gear, etc. Your goal might be to shoot any old deer, take your limit of ducks during a one day outing, find and tag that ginormous elk you saw last year on the last day of the season, or hunt a new GMU out West.
To hunt smarter, to me, you look at how you have been doing things and then think about how you could do things differently to get closer to the goal you want to achieve. For example, if you have been camping at the trailhead and only hunt within a mile or three of your camp each day, but don't see any decent sized elk (or any for that matter), hunting smarter might mean you decide to carry a spike camp with you so that when you find the elk you can stay there overnight and be on them in the morning. Another example might be hiking in 3-5 miles and settng up your base camp so that you are away from the areas everyone else is hunting and let them push the elk to you.
If you get into game animals after walking ten miles every day but you are exhausted because of the weight of your gear, then hunting smarter might mean getting lighter gear or reducing what you carry or getting in better shape or all three things.
Hunting in a drainage that has a road running along its bottom to faciliate getting your game out is hunting smarter rather than harder. Sitting on a ridge line glassing for bulls instead of walking 15 miles to try and find them is hunting smarter not harder. It all boils down to your saying, "There has to be an easier way!" and then finding that easier way.