In a portrait painting beginning painters often put in too many details and make them too sharp. For example: Cutting edges around the eyes, hard red lips, pointed corners of the mouth etc. etc. Why? One of the pitfalls is working from photography.
As you know, I do that too often myself and I don´t approve of it either. But there is always the risk that the painted portrait becomes a literal copy of the photograph. And that’s exactly not the intention. It must become an interpretation of that image. Your interpretation! So forget about all the small details and try to keep the statement simple. The simpler the stronger. Remember that the likeness does not depend on an accumulation of details. The above image is a quick demonstration during one of my private workshops (using photography that was not made by me). Take note of the softening of the details, the eyes, the mouth, the eyebrows.
The other image is a portrait done from a live model. Working from observation there is less danger of killing details, especially not because it needs to be done quickly before the model gets tired. It calls for a smooth approach. It is the simplification that helps you to achieve a good resemblance.