some very basic tips that help me :)
-never use straight black (i normally use deep blues, reds, etc, or a dark color from the environment if i have a background)
-find which direction your light source is coming from to help determine where you will put your shadows
-i also personally use two layers of shading (one for the general area and another for deeper shadows to help with depth)
-adding highlights is never a bad idea to add to a piece c:
-for layer settings i use the multiply mode for shading and dodge/overlay for highlights
Spring Month: 3 
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Heavy Rain Moon: 
