As we all know, making mistakes is part of the learning process. More often than not, you just have to learn things the hard way.
But if you’re lucky, someone who has already done something stupid will tell you about it, and thus spare you the bother of repeating the same mistake.
* Leaving the lens cap on when preparing to take someones picture.
This is something I’m sure everyone has done at least once, and isn’t such a big deal really. But doing this when photographing a TV anchorman in the middle of huge open office area, full of media people watching their coworker being photographed? Priceless.
* Using your new flash on assignment before properly learning how it works.
Shortly after getting my first Speedlite (in early 2006 this was) I was hired to photograph a prominent Icelandic politician and his equally well-known wife. I hadn’t read anything about the settings and just decided to wing it, and spent a good deal of time and energy fooling around with it while talking a mile a minute, hoping nobody would realize that I hardly knew what I was doing. Needless to say, the best photo I got that day was taken without the damn flash.