Realistic sketching with coloured pencils - a portrait of Avril Lavigne

I’ve always admired people who can get a photorealistic finish on pencil sketching. For some time I wondered how it was achieved. Then I discovered burnishing. I knew some blending techniques but hadn’t really attempted burnishing before. (There were some serious gaps in my art education!)
This is my second serious attempt at intensive blending, Avril Lavigne. The blending and colours seem to be working well.

With any artwork I always find it best to “sit on it” for a while. Looking at a picture after a break helps you see the flaws. The errors are glaringly obvious.
Take Avril here, I thought I was finished until I scanned the picture in. But now I can see where I need some minor adjustments. But I’ll do that tomorrow I think, then add the picture with changes.
I can also see that I need to clean my scanner bed, there are marks on her chin which aren’t on the original! Ugh housework! (phtew)