What helped me to learn to sprite was just a lot of editing of existing sprites. I started with simple things - hair recoloring and what we call "frankenspriting" - that means learning to cut and paste from existing sprites onto others. How this helped is really gave me a chance to see how the shading and construction of sprites works. I highly recommend doing a bit of it before starting from scratch.
Just a few pointers that may help with sprites. MV sprites use a color palette of 4-5 shades for each "piece" - hair, a shirt, etc. The first thing I do when spriting is start by making a color palette. Usually, I just open a bunch of existing sprite sheets and look through until I find something that is about the color I want to use. Then I use the eyedropper tool to make a run of shades, selecting each one and drawing it next to the sprite, so I have all the shades to make up that color. You can see it in the image below.
A few other tips in this picture. #1 - MV uses black to edge the bottom of a lot of things - hair, shirts pants. #2 - The darkest shade of your palette or run is used to outline the right side of the sprite's hair, as your light source is from the upper left so it will be lighter in color. #3 - The second darkest shade is used to outline the left side, for the same reason.
Clothes are a bit different, there isn't always the lighter on left, darker on right side. Usually, the darkest shade outlines both sides with your lighter colors in the middle to give a bit of a rounded or shaped appearance of the body. It's a bit tricky to learn how to do just right.
I hope this helps a bit. I strongly encourage you to play around with editing existing sprites. Take a color palette from one sprite and use it to change something on another - it will really help give you a sense of what shades to place where and see how each tiny pixel can have a dramatic impact.