Yep, I have some! You draw in color, right? I'll just assume you do... I'm sure there are other methods, but this is the one I use, and it works pretty well for me. If you have a tablet or can get one, I recommend it. Shading and drawing are HARD without one... my tablet was only about $30 (I have no idea what the conversion is, sorry, but that's pretty cheap.) and it comes with a mouse that can be used for clicking, zooming, etc. and it works quite well!
Anyways, I do pretty much everything on a separate layer, including shading and lighting (two separate layers)
color everything in the flat colors that you plan on using, then go to another layer.
On this layer, plot your light source. Light spreads, so make it conical. That means not all your light beams go the same way, so if you have things that stick up or out (like the head on a dog) You'll have to figure out the angle the light hits that object. it's not hard. pick an angle between the two angles of your light edges and stick to it. Use a random color you don't plan on using in your shading, lighting, or coloring layers so it sticks out. Make sure this layer stays above your colored drawing, but under the guide layer for what you're working with. This layer might have to move a couple of times.
go through on yet another layer (It'll go away eventually) and plan out where you're going to put your shadows. If you need help, find a similarly shaped toy (hey, I still have all my toy dinosaurs and animals, nothing to be ashamed of) or, if you can't find one, look up a picture of whatever you're drawing (If you're drawing OC X, don't look up OC X... look up a character with a similar hair/clothes/body type. If you're drawing a horse, look up a horse; if you're drawing a duck, look up a duck; so on and so forth, etc. etc.) Anyways, put the line at the VERY EDGE of the shadow zone, where you're not sure if there's shadow or not. I prefer black lines for this, since it helps keep guidelines separate (you'll need another set for lighting)
Now go to your shadow layer. Use a darkened, almost completely transparent version of the color you're using. Zoom in as much as you can. Shade everything from where the darkest part of the shadow will be to where the shadow will end. If it looks stupid (I'll be the first to admit it when my shading looks dumb, just own up to it and you'll be fine) then the brush isn't transparent enough or the color is too dark/the wrong color. hit undo and do it again. Keep in mind that every layer has to be one continuous stroke. If you go outside your lines, use the eraser after you've finished coloring that layer. The first layer really shouldn't look like you did much of anything. Move on to the second layer. You don't need to switch actual layers, it's just another coat of digital paint. Same color, same transparency. start this layer just a tiny bit in from the outer edge of the last layer and bring it all the way to the core of the shadow. So, hopefully now you see where this is going. lots and lots of layers, offset just a little, covering the whole area to get a decent gradient. If you realize that your darkened color is no longer making further shadow because it's become opaque from all the layers, darken the brus a touch more and pick up from where you appear to have left off. Never let it get to true black unless you're shading something very dark. If your subject is black (black horse, black cat, black dog, etc.) make it an untrue black, a dark blue-gray or navy blue. Use even darker navy (never use gray shadow on a blue subject. it looks awful) until it won't darken any more, then use black. Use black for the lines on these characters, just like any other. Don't worry about being able to see the lines or not. Highlight on the less shadowed side of a line that separates shadowed areas. Use a bright color for guidelines in shadow.
Now for highlighting. Make a layer on top of your shadow layer. Make your guidelines (I prefer white for lighting guides) to outline where the light hits your character. This is just like for shadow, but where light hits.
Now, if you're using a neutral light, just lighten the color. If you're using a colored light, you'll have to add that color to your color and lighten (note: I've never had a good effect with a colored light. It might just be me, though). If you're dealing with searchlights/uncolored spotlights/strobe lights/headlights, use pure white (those lights are BRIGHT). Don't forget transparency!
Go through and do your lighting just like you did your shadows, but less intensely (unless you're using a REALLY bright light)
hide (don't delete!!) your guidelines and light lines, zoom out, and look at the picture. figure out what needs to be tweaked. Tweak it. You're done!
(You can delete your guidelines now)
