I think partly it comes down to what you think of as “devious.” Deception is an essential part of warfare, but I wouldn’t necessarily equate that with being “devious” in the sense your OP seemed to indicate.
Perhaps I am biased, however the former Military Intelligence officer who educated me in deviousness in my youth began with an example from warfare that while a tactic, I would describe as devious. To wit: You are a sniper, and you see a column of advancing soldiers, how do you maximize your combat effectiveness? Answer: Your primary target is the foremost member of the column, his wounding or death will stop the column and motivate them turn the opposite direction to seek cover. At this point you should focus your attention on the rear off the column to produce the same effect. This gives you the maximum numbers of targets visible in the chaos. At this point you continue your attack until fire is directed your way and then move to an alternate position to retreat or re-establish your attack. He used this as a deliberate introduction into deviousness, without saying it wasn’t a necessary tactic in war.
How is that devious? I don’t see how it can even be described as “deceptive.”
Very well, anyone who doesn’t consider it devious need not contribute anything to the thread related to what they don’t consider legitimately devious. If anyone agrees with me, please add your opinion.
Stop telling people that you have an interest in being devious. (It gives you away 
)
I consider the admission made that I would like to be devious to be worth the potential increase in my ability to do so. It’s a calculated risk. I do appreciate the advise though.
Ah, I see. Well, to adopt a tone appropriate to the thread, in that case I suggest you check out www.realultimatepower.net 'cause those guys are deceptive and flip out out and kill people and are totally sweet. To quote, “Ninjas can kill anyone they want! Ninjas cut off heads ALL the time and don’t even think twice about it. These guys are so crazy and awesome that they flip out ALL the time. I heard that there was this ninja who was eating at a diner. And when some dude dropped a spoon the ninja killed the whole town. My friend Mark said that he saw a ninja totally uppercut some kid just because the kid opened a window.”
I’m sure it’s just what you’re looking for, bro.
No actually it’s not. As I said, I want an education in a practical skill. One that has been practiced and is still practiced daily by the vast majority of the human population. I’ve studied the long and the short con as well, more excellent examples of human nature at work. As is any salesperson whose true income is based on commission. The characters in “Glen Gary, Glen Ross” for instance.
Take one slice of meat off someone’s sandwich in the lunchroom. They won’t notice it and you’ll have free meat! Devious! 
I realize this is IMHO, and feel free to continue posting any replies however I was considerably more optimistic that more people would post serious answers.
As a devious person, what do I gain from revealing my secrets or educating somebody to become another competitor?
Serious about being devious? It’s just not a serious topic. Of course you’re going to get jokey replies.
Speaking from experience: utter balderdash. Stick with the ninjas, kid.
The book, The Big Con, has been used quite a bit in Hollywood as their guide to thinking up convoluted schemes to fool people. I haven’t read it, but the reviews are good.
Offer a single suggestion that has nothing to do with your secrets only general deviousness, you can thereby increase you ability to be devious through the replies you help promote in this thread and benefit from it without having lost anything.
I disagree with your assessment that it’s not a serious topic, however I didn’t say for people to quit posting ‘jokey’ replies, just that I had hoped for more seriousness. Feel free to mock me if you want (not only is it your right, but I’m sure it’s fun), but I am serious. Deviousness, manipulation, power politics, whatever you want to call it makes the world go round. I want to improve my skills in this area, I mentioned sources like Machiavelli’s “The Prince” every decent lawyer and most educated businessmen read this book as part of their education. I’m just looking to extend my syllabus.
Getting to Yes – a classic on negotiation.
Got something to sell? Learn all about devious pricing schemes in Priceless: The Myth of Fair Market Value (and How to Take Advantage of it
Thank you very much
I appreciate your data point. I have known someone whose life’s work was always based on commission they pursued a devious strategy in common with all the people in their field until they had life altering experience. They then changed their strategy and decided you could make more honestly than by being devious with your customers. Then of course they had to spend all their time being devious with their competitors in order to offset the disadvantages of being honest.
I do want to offer you ‘props’ on the use of the word balderdash. This is a word that needs to be used more often.