Hello!
A lot of beginner pixelart mistakes here.
do read www.pixeljoint.com/forum/forum_posts.asp?TID=11299A lot of pillow shading, unnecessary colors, low contrast(even though it's a night scene)
It's fine, lose all the details. You don't need an overload of details, just need to imply the details that matter and help to convey the object's nature/texture/material. Otherwise it's just ugly noise!
Let's take it one step at a time. REDUCE colors, lose gradients! Fix pillow shading(Establish a light source)
Look at some pixelart references. (Just google them/ search on pinterest)
See how others do it, try to analyze and compare, see what you're doing wrong, attempt to iterate and fix upon it.
Again with the clouds(Which is apparently a rock), LOOK AT REFERENCES! Whip up google images and search "clouds in sky" or a "Rocks" (Not to be confused with The Rock)
Do they look like that?
Good luck, I expect progress the next time you post