For Making A Skin:1. Select a skin maker that suits you, I use MCSkinEdit, it is for mac and windows
2. Have the idea of what skin you are doing in your mind
3. Open google images and get a good picture of what you will try to do, not a minecraft picture a regular picture
4. Try to copy what is on google

For Shading:
1. Select the skin shader that suits you, I use minershoes.com, it is online for mac and windows
2. Begin Shading your skin, it is easy, I will tell you how
How to Shade on minershoes.com:
1. Make a regular Skin that you want to shade
2. Go on minershoes.com
3. Scroll to the Middle of the Page
4. You will find a skin Template, it will be flat and next to it a skin that will be 3D, above the 3D skin there will be an upload button, press on it.
5. It will open something, look for the skin you made, be sure to be in the MCSkinEdit folder or else you will never find the skin that you made
6. Select the Skin that you made
7. It will come instead of the other skin that was showing, press on the part picker which is something at the bottom right corner that looks like a pen
8. Select the Part/Color that you want to shade.
9. Then click on the brush which is on the top left corner and go on the part that you want to shadeFor example: if the shirt is blue and the pants are red, you want to shade both the pants and the shirt, you select the part picker then click on the shirt then click on the brush and only shade the blue parts, if you go on the red it will become blue so when you are done shading the blue shirt click on the part picker again and then click on any part of the red pants then select the brush and go only on the red parts.
I wish this Helped :)