Blows my early painting away. Very nicely done and you especially did a good job with the gold--very clean

. Improvement will come with time and the more you paint the more you'll begin to find that a lot of the professionally painted miniatures are just a combination of silly easy techniques like layering and washing and drybrushing.
One of my first paint jobs when I started painting was the tactical squad from the Battle for Macragge. I drybrushed all the marines blue and the boltguns silver.
It took me 3 years and many destroyed
GW brushes to figure out that watering down paints before applying them makes the miniatures look sooooo much better. Anyway great job.
My tips for you:
Look up different painting techniques and try em' out (layering, etc...)!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Try out different colour combinations.
Paint from dark to light (once I started doing this my painting improved DRASTICALLY).
Get more paints (so you can bring out shadows more and get different tones. For example, for skin paint a dark skin tone, then go lighter on the raised areas leaving the recesses dark (if you really want nice skin paint an eaven lighter skin tone on the ultra raised areas still leaving the 2 darker tones exposed)).
Keep painting and enjoy it!