Cerbero is to credit for the cover (I also used his art

If I may make a suggestion based on your sample?
1. First adjust your monitor
a. Set your monitor's color temperature (white point) to 6500K
b. Set your monitor's brightness control (SO misleading - this is really your black level

c. Set up your viewing light (do not have lights pointed directly or reflections from rear lights)
2. Now, go adjust your television also

Once you do this you'll notice that your demo cover posted above has about four shades of black, PLEASE do keep posting your art as when Lars4mf started this thread that was the intention to show off your works, yes true some are a bit out there and really should not be printed but hey we all have to start somewhere and it's not always pretty.
Keep up the work and I look forward to your covers being added to the Covers Collection!
RiK
P.S. Use this link to get your monitor adjusted - FIRST get a drink and snack and read away!!