I'm not overly observant but the ones listed below did leap out at me. I will continue to update these "oddities" posts as the season continues (and there will be a Season 5 one in due course).
Beach Hut Man in "Impossible Astronaut":
This has been widely reported and speculated about and to illustrate the point (and please click on pics for HQ versions):
Now it could be a member of the crew accidentally wandering into shot. However, following the events of "The Rebel Flesh/Almost People" the Doctor knows that Amy etc saw him die - and we can see from the recent trailer that he learns the date and location of his death. So, is this "our" 900 year old Doctor watching to see what happens? Is the beach hut a disguised Tardis?
"Curse of the Black Spot"
A couple of things in this one - first up, the missing pirate. The boatswain in the magazine/armoury disappeared after the Captain and the Doctor returned - could have merely been bad editing of course. There's also the curious fact of the Doctor saying the virus that killed the alien was a human virus that came from "our world". Now why would he say that? Mistake? If so, this was a very obvious one that surely should have been picked up in the early stages.
"The Doctor's Wife"
Just one question. Why did the Doctor's sonic glow blue?
There was also speculation that the Doctor's bow tie changed colour in "The Rebel Flesh" but I have dismissed that as merely an effect of the strange lighting of that particular scene.
So - mistakes or something very deliberately plotted by Steven Moffat? Time will tell - and please let us know if you've seen any others.