You can learn much from your failures, but you can learn equally from your successes. Case in point: this shot.
I was approached by a friend, who needed some pictures taken for a job she was applying for. She sent me the list of requirements for the pictures, and boy were they long.
And on occasion, contradictory.
I wasn't sure I was good enough to take the pics, but I said I would try. So I read and re-read their requirements, pulled out some of my photography books on lighting and poses, read some more, and set up my gear.
I had a black cloth backdrop to absorb some of the light, she (and my snake, Pokey) in front. A hair light shining down from above, one strobe at a 45 degree angle on the left side about 4 feet away, and another one at 90 degrees from her at the same distance.
I used my 50mm lens at F/14 (now, a sidetrack here: F/14 isn't a "real" f/stop in the classic sense, but it worked in this case) set the ISO to 200 and shutter to 1/250.
One of the requirements of the shots that are submitted is they cannot be photoshopped in any way, straight from the camera only. So what you see is what I took.
I took about 30 shots, and she submitted the ten best. All ten were accepted and she got the job. I was super happy for me, but also for myself, for it showed I could pull off demanding shots in an area I'm not well versed in.