It's tough sledding and hard on the eyes and neck, but searching for errors/varieties/misstrikes adds a level of excitement to every coin you look at.
For varieties, I picked up a 2013 Red Book at my LCS for just five bucks since the 2015 Red Book came out. It helps having that handy. If you have an iPad or a laptop next to you while you hunt, I also like to pull up the Top 50 list on the Lincoln Cent Resource website to refresh my memory on what I should be looking for. It took me months to remember the smallest details, and I have a lot more to learn, but eventually you'll get those intricacies down and they become second nature to you.
For errors/misstrikes, it's dumb luck. You just have to be patient enough to actually look at each coin. So far, I've trained myself to be patient enough to give a once-over to the obverse. I'm still working on convincing myself to look at each reverse.
