TerrenHurley

Answer: Honestly, what made me start to notice revealing mistakes/visible crew was just learning about those types of mistakes on this very website and figuring out what to look for. Watching behind-the-scenes materials and learning how movies are made also helps. If I'm specifically going through a movie or show looking for mistakes, which I do sometimes for fun, I usually load up a Blu-Ray copy or the streaming service I'm using, and just scan through every shot, frequently rewinding and looking at all the little details. It can be subtle, so you may have to watch the same few shots 3, 4, 5+ times before you notice things. And even then, I'm sure I miss a lot of them.

TedStixon

Answer: First, it's imperative you watch a film or show with the ability to rewind (DVD, On Demand, Streaming, etc). Second, you should be familiar with the different types of filming techniques and procedures so you can visualize how the scene is being shot and where equipment and crew might be that could accidentally get in the shot. A lot of wide shots are going to expose revealing mistake, often time just briefly. While a continuous shot (where the camera doesn't cut) isn't going to have continuity issues. When the camera angle changes, that's when you can pick up mistakes. Finally, you can't be a passive viewer, if you're texting or looking at your phone, you're going to miss mistakes. And if you're really out to find mistakes, you'll probably miss the show (so it's best to look for mistake on your 2nd or 3rd viewing).

Bishop73