Hi Sarah! This is a critique you've requested as a prize in `lintu47's contest.
You've mentioned in the description that it's your first portrait with coloured pencils - well done! It's a great piece for a first try. I can also see that you've already submitted another portrait to your gallery in the mean time (the one of Frodo) and I've noticed some improvements in that new one, so I'll mind that while writing this critique.
Let's start with general stuff - you've captured Sparrow quite nicely, I can definitely tell who's that and I'd tell either even if this character wasn't so specific, these are Johnny Depp's face shapes for sure. The anatomy is mostly correct - there are minor flaws, like the diffrent sizes of his irises and cheekbones, but that's nothing serious and easy to correct - and I can see improvement conider this matter in your new Frodo portrait. I also think that adding a darker shade on the bottom of his nose would make it stand out more, it looks a bit flat right now. Looking at the reference photo (which I believe is this one; you should have included a link in the deviation's description), you can see that the nose has that darker shade - your drawing lacks it because you didn't include the light contrast between each half of his face - and the nose's bottom's shade comes from a shade similiar to the one on the right half (right side according to the viewer). But then again, you've improved that in your newer drawing.
Hair looks not bad, however, you tend to repeat a common stereotype about drawing hair - one single line after another, presenting each single hair. It's not a 100% wrong way, but in most cases it makes you forget that hair is a mass forming just another shape - and as any other shape, it has its "general" chiaroscuro, just like an apple or a cube does. Let me show you an example - Molly Hooper drawn by `alicexz. Can you see how it behaves with light? You can tell exactly where's the light source - and while hair still keeps its shine and structure, it also forms the mentioned shape, it's not just a flat stain. You can see a similiar thing in your photo reference - ligher on the left, darker on the right, although this case is much harder and the contrast is not so easily noticeable. So to sum the hair part up, it's not a bad thing to draw single hair after another, but you should remeber about seeing them as a mass, not only details.
Shading and colours. While there are flaws that you've improved in your new portrait, I'll mention them to show what you might be still missing. The best example is the skin: in this drawing you've used many diffrent brighter and darker parts to form it, but they were all brownish, peach, pinkish - which is what most people consider skin tones. However, you've proved in your portrait of Frodo that you started thinking more consciously - you started using purple and gray instead of darker versions of the same colours. That's a very good observation and definitely an improvement compared to this portrait of Sparrow. Think even wider - after improving skin this way, think of doing the same with everything else in the drawing, hair, eyes, cloth, background. This, of course, refers to realistic drawing and painting.
That would be all, I suppose. Once again, this is a very good portrait as for a first try and while it has some minor flaws, you've already shown us that you can improve and I believe that you'll keep it up. Good luck!