Yeah, I'm sort of a fail with tilesets, but I tried. This is just the first attempt at a tileset that has been in my head for some time. Don't worry, this crappy pic isn't the final piece; I'm going to add more details and shading, and make a few more trees and plants. Opinions are accepted. ^^
(http://i1238.photobucket.com/albums/ff481/hidakakufangirl/tilesetpurplewip1.png)
Generally Speaking:
i would like to see how you incorporate a purple forest into your game. what's the purpose? i'm curious. so in review terms: the quality is lacking, but it's not hopeless. my guess is you're trying to replicate the standard rtp. i find it very hard to create resources from scratch (and i don't know if that's what you're doing here, but if you are...try not to. it is very hard to make original content mix seamlessly with the rtp).
I Recommend:
i don't know how the graphics specialists at enterbrain made the original graphics for rmxp / rmvx, so i typically stick to heavy editing at best. if you don't use the general methods used to produce the original work, then your work will not mix well with the rtp. i recommend using a photo editing program and simply changing the hue of the original forest tileset to reflect the desired effect.
For a WIP, I'd say it looks good. What are you using purple things for?
I've been using GIMP a lot to alter existing stuff. The only things I've made which required a lot of "hand-made" graphics are icons, and a few characters.
To echo what the poster above said, yes it's not always easy to get it to fit in with other default resources. I sometimes find it looks better if you make the graphic you want in your game, and then use a tool (like GIMP) to drop down the contrast and brightness a little bit. I'd avoid using the darker shades of colors as the default graphics (to me) seem to avoid the extremes, and never have too high of a contrast.