Hello, people! As you can tell by the title, I'm about to going to give
you some art tips that might improve your drawing skills!

In Microsoft Paint, it is possible to ink a sketch and remove the sketch
and keep the line-art as if it had layers!
Here's how:

• First, do the sketch. (I suggest sketching using blue, red or green, anything but black.
  
• Ink it using line and pencil tool.

• After you finish inking it, select the EXACT color of the sketch, not something close to it. Use the eye-dropper tool to select the sketch color, then, select the eraser tool, then, right-click. That way,
  only the sketch shall be removed!!

And, here's a shading and lighting tutorial that might help you.

• Shading is determined by the light in the drawing, seen or unseen. If it's unseen, imagine there's a sun or light source around the character or object, the closer to light source, the lighter, the
  farther, the darker. So, if it's kinda close, add lighting to the side
  where the light source is, then, on the opposite side, add a darker
  tone, but, not too dark or it will completely mess up the drawing. And,
  if it's a character, you must add shading under the chin and on the
  neck. When doing folds in cloth, look at folds in your shirt or types
  of cloth you have and add shading according to that. So, basically,
  it's the like this: Lighter, normal, darker.
• And, there's another thing: secondary shading. Secondary shading is used a lot in anime. Next time when you watch an anime show or see an anime drawing, look at the shading and observe. That might help you,
  too. Secondary shading is shading for shading. A darker tone than the
  shading, but, remember: NOT TOO DARK!!!!!!!!!!!!

And, the lighting is the same if you add something like lightning or
fire. But, with fire, you might want to add red lighting. You'll under
stand why if you examine a picture of something close to a fire.

I hope you found these useful.