I don’t concentrate at all, however, a lot of times I see to play elaborate Xanatos Gambits (on a few occasions, Xanatos Roulettes). I tend to do better in games with lots of rules and loopholes, especially ones that can accommodate house rules (i.e. are not hardcoded). I’m not good per se, but in open RPGs I get a thrill out of manipulating people left and right, in D&D one of my characters have been described as “mind-rape” characters, to the point that I have an envelope with dozens of contingencies (signed by the DM and mailed to myself to prevent cheating), a foresight bordering omniscience (in part my character, in part mine), and the ability to wrap just about anyone around my finger.
I can do it on a smaller scale, I’ve only gotten that elaborate once, and my DM forbade me from ever using that type of character again (well, except last time, but we got to Death Note levels of everyone having an elaborate scheme to the point where we BARELY won because we out-planned the enemy by ONE event, it was practically setting up dominoes). Oddly enough I suck at RTS and TBS games, probably because I hate learning all that build order stuff and enjoy more “free” strategies that involve out of game limitations. I’m okay at simple fighting games, preferably ones with more than two players (Smash Bros is perfect for this) because I like faking out and manipulating players, however I don’t have enough reflexes to play at the higher level, and my lack of such tends to get me beaten (I know HOW to win, I just can’t do it).
But I never try to “concentrate” I just let things play their course, I get a KICK out of planning, it comes naturally in those situations. I have tons of crazy stories from RPs going terribly, terribly wrong (well, for everyone else most of the time, sometimes myself).