My First Digital Art: Skulduggery Pleasant

Valkrie: You are such a moron
Skulduggery: Don't be jealous of my genius.

So this is the first time I've ever done a digital painting (apart from a few little doodles to get the hang on the brushes) and at first I had no idea what I was doing, and I slowly started to get the hang of it. For this I used a wacom bamboo pen and touch and spent quite a few hours on it, I also used a reference picture.

I had started this a few weeks ago and then one day, by sheer luck, I happened to see an advert on tv saying that Derek Landy (author of Skulduggery Pleasant for those who don't know) was coming for a tour to Australia to promote his new book! I saw this as the perfect opportunity to get this signed by him woooooo!

Since this is only my first try and I am such a noob at digital painting, I would really appreciate any words of advice and ways in which I can improve. So, if you see stuff on here that I have done wrong or could be done better, please let me know Cheers!

And now a final parting quote from the man (or skeleton) himself:
"Doors are for people with no imagination" - Skulduggery Pleasant