Can some one tell me some tips on shading?

TRADITIONAL-
PENCIL- Start by lightly crosshatching the darker areas, and then go over the whole lot, pressing harder where the darker areas are.
PRISMACOLOUR PENCILS- Press harder where you want darker areas, and smudge highlighted areas with white pencil. Smudge darker areas with black.
TEXTA- Use darker textas for darker areas, OR colour the whole thing 'flat' and then shade over darker areas with black pencil.

DIGITAL-
SUMOPAINT.COM OR GIMP- Flat colour the whole picture, then use the fuzzy select or magic wand tool to selent the area you want to shade. Pick the brush tool, with the fuzzy outline. Make the brush black and toggle the opacity for shading. Continue until finished.
PAINT.NET- Flat colour. Use the fuzzy select or magic wand tool to select the area you want to shade, then use the line and curve tool to shade. You can pick either a darker/lighter shade of the colour you want to use, or toggle the transparency on a black/white colour setting.
PAINT.NET w/ GRADIENTS- Select a new layer UNDER the lineart layer. From there, drag a gradient across of the colour you want, then erase it from the areas you don't want. Add and merge layers down until compleate.
MS PAINT- Use the pencil tool to scribble in a darker shade of the colour you wanted.

I hope this helped. Just a basic run-through of shading on my most used techniques/programs.

If anyone would like to request a full tutorial with any particular style I do, please inbox me.

The picture below is done on paint.net. I used a gradient for the sky, then worked from flat colours to shade in with the line and curve tools. I done it maybe AGES ago. xD'

Art, Mef- (c) me.
Johnny C- (c) The Almighty Scolex.