|Greetings from the Critique Club!
"The sign of a photographer: Take a mundane subject and turn it into art"
This was an unusual challenge in that the object was to take an ordinary household object and create an interesting photograph from it, all within in a time frame of 24 hours.
Your composition pulls the eye right to the main focal point - The Tacks. This accomplished meeting the challenge with a bull's eye. The strong presence of the tacks in the shot keep the eyes from wandering around, being distracted by additional objects in the image. The background, while colorful, is supplemental and not over-powering as the depth of field drops it strongly out of focus.
Your subjects are well lit, and you demonstrated a fine job of placing the sun directly behind one of the tacks with just enough flare on it's sides to recognize what it was, without blowing out the shot. The glow on the tree bark and the colors cast in the background trees balanced this out well.
You have a good handle on your post-processing in this picture. The tacks have a natural color, the sharpness is good and overall the image is not over processed nor over saturated. The simple border applied was complimetary to the shot and the color chosen feels right with the overall look.
I think after studying this for a while, I have found little to suggest in ways to improve this image. One possiblity would have been to change the order the tacks were arranged so the upper tack would have been a darker one and would have stood out a bit more against the bright background.
I hope this was useful to you, and please feel free to contact me via PM if you have any questions regarding this critique or anything else relating to the site in general.
(On a side note, you were the recipient of my very first critique here)