It is always good to have figures painted and your figures improve the game a lot. But there is also space to improve your painting.
I've played Warhammer 40k for several years and learned a lot about painting when I spent time in the shops. Your figures are very good painted - for using enamel. But there is a much better choice - water based colors from Citadel. Let me tell you the steps of painting and about the two techniques which make the difference.
The start is more effort. You have to prime the figure. Paint it in white completely, best is a spray because the color will be equally thick at each point and don't "hide" details. After this you paint the figure - like with enamel.
Now you take the color you used, let's say red for the dragon. Mix it with some black until you have a really dark red - 2/3 black 1/3 red. And dilute it with water until it is really a liquid. 1/3 color 2/3 water. Then you take a large brush and paint the complete figure without caring about any details, just everywhere. The diluted color will go into all "cavitys" (don't know if the wording is perfect). You will have darker color at all places where shadows should be.
Of course the complete figure will look a little bit dirty afterwards. So you have to drybrush. This means you take your red, mix it with a little bit yellow and put the color on your brush (a very hard brush) and paint until the brush is dry on a piece of paper - until no liquid is left - just dry color. Then you move the brush over your figure with some force and all parts which are higher become lighter. Do this several times using more yellow/white and less force - that will look three dimensional.
That's a brilliant example: (better than I can do)
(for the scales, the technique I described could be used)
That is what everyone can do: