I have read similar accounts of the 1800 plateau even by people who went on to become titled players. Their assesment was the same as yours. At or around the 1800 level, the player with the best plan wins. Doubt if I'll ever be faced with that problem, but it must be frustrating. On the other hand, you now have the opportunity to play "real" chess, an experience most of us patzers will never know.
Plateau
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It feels like my "casual" days are over. I need to either get serious about improving, or start to enjoy losing!
I think you're only allowed to change your "handle" once, so as you said you need to either become Serious_Joe or Loser_Joe. Sorry, I just couldn't resist....
I'm climbing towards 1600 again in blitz, let's see if I can top my best rating 
if u get higher in corespond chess then u get those srs databas nd engin user... just pointless tbh
Also @ Casual Joe, You've only played 30-40 games. I think you are actually playing around your strength now.
For the most part my approach to chess has pretty much been to try to play solid moves (avoid pawn weaknesses, seek piece activity, etc) and avoid blunders. Usually my opponent would eventually blunder or get into a lost position, and I'd win the game. This approach served me pretty well until I got to about 1800 strength (according to my chess.com rating). Since then I've found that opponents are beating me, and I don't even know what I did wrong! In order to improve from here, I think I need to move beyond the "follow the basic rules" philosophy and actually start devloping some subtle plans. This is hard!