I understand using SD3 for reference, as it contains a glorious amount of gorgeous graphics, don't even get me started about their cliffs! But the thing is, many people, when starting tiles tend to copy it. Idk if you've had tile experience before, but jumping into something as intricate and complex as sd3 may be something to warn against. Though, definately, studying the technique, and finding applications for them is highly encouraged. The old masters of pixel art.
The thing is, is that it is immediately recognizable almost to the point where, at a glance, you have to question authorship. What I mean is, this right now, seems like a blatant imitation, instead of an application of techniques derived from the game itself. The colors are part of this, it looks like you used their same colors and copied the 'ideas of' their grass and dirt tiles, without actually 'ripping' them.
Ok, with the actual tiles, your dirt is far too blocky, because of the squarish grass meets dirt tiles, I would recommend diagonal/rounded corner pieces. The house/building is a little too early to say, but it seems weird. I would change the contrast/relationship between the roof and the building, because the depth is off. Also a good way to test how well the tiles work in general is to have a sprite to compare it to. Essentially, all the tiles should be built around the sprite, because they compliment/play off of each other and set up the perspective, depth and priority. Hope this is helpful, also interested to see updates/progress if you do this every day.
Although I love sd3, idk I guess I just see it copied too much that I develop this kind of reaction. There are some beautiful snes games out there to learn from, and remember, these old masters weren't always perfect themselves.
