The clues of misdirection seem to be:
Several scenes shown twice but with different words used
Mary dying in a way that she once said wouldn't happen (jumping backwards when shot and spurting blood)
Stories introduced for no apparent reason (the fling)
The stupid Bond-esque dialogue
The baddie revealed to be someone who'd only been in the episode a few seconds
John's constipated howling (Martin Freeman is a better actor than that)
John not being in the room when Mary was shot, but entering the building with Sherlock
The jpeg/blog post: For those that never saw it, John's blog is/was available online during the last series. It had details of cases we saw but also references to cases that we didn't. One of the latter was The Six Thatchers. This has not been taken off the blog. The blog now says that John Watson doesn't update it any more. This blog was a big part of the Sherlock universe accessed by fans and with clues on it. Highly unlikely they'd just abandon it. So it's quite possible that this is actually a clue in itself and the jpeg shot was not a mistake.
Dunno. Like I said...we'll see.