I believe that details don't make a painting. A successful painting relies on good composition, value, shapes, and color. Adding details will make a good painting great, but they do NOT make an unsuccessful painting works.

However, detail can be a great storytelling device. Some rusts on the rooftop tell you that the house is old and weathered, umbrellas show you it's raining in the scene, some light and dark strokes in the background hint you that there are cars in the distance and etc...

In my painting Enoch, I decided to put some details on his cloth. He had that on in the photo which I painted from. But I put those details in because it is memory of him, it adds some interest when you look at it, and it tells you that this is important to me. When Enoch was little, everyone calls him "little sheep". He has a sheep blanket, a stuffed animal sheep, and, of course, this sheep baby outfit that he was wearing. And that is why I choose to include this detail in the painting.

So ask yourself "What is important to me? " when you paint. If you paint every little detail you see, you end up loosing them all because they become noise. But if you pick and choose the details that are important to you, they become great storytelling devices.