My tile grid looks like this: (without the 1 pixel line between each tile; placeholder tile)

The lighting comes from the upper-left corner of the screen.
Here's one casual attempt I made:

Using this to multiply with the tiles, to create shadowing:

I mean, it's not bad (well, yes the image is - but the basic idea isn't bad), but I'm thinking I'm going to need better than that. Maybe some yellow tinting on the sides facing the sun, and blueish tinting on the sides facing away.
I'm looking at some photos of hills on Google, but I want real artists' perspectives on it, myself being more of a programmer than designer or artist, and so less in tune with visual trickery.
I'd like to be able to multiply or blend other "mask" images onto regular tiles to create the correct illusion of depth and slope and lighting.
I'm not yet ready to fully start producing the art for this part of my project, but I do need to knock up a few test examples to see whether I can actually create something passable - as I need to know whether hills are actually possible or not in my game, as it'll effect the layout of my game world.
Any wisdom and tips you can give me is much apreciated!













