the grass is EXPONENTIALLY better… still, materials need a little work… (still too green… plant life is usually darker and not so much just one color… usually has a more yellow tone…) one thing you might want to do is use a blend texture as a stencil for a cloud texture so that u can simulate a little dirt on the grass near the base… this would help cover up the seam between the two
now for the ground… waaaaay too yellow… sand is very brown and suprisingly has a fair ammount of blue mixed in with the red and green… if red and green were about equal, blue would be up around 2/3s i think… it shouldn’t be too far off from the dead flower’s color… why is there green in the ground? if it were from above the grass I can see why there would be, but dirt isn’t really green… I don’t really like the texture on there with all the spots, it makes it look just kind of bad… I’m guessing it’s a stucci set to normal? if so, turn down the nor effect a tad, and make the stucci a little bit smaller so it doesn’t look so much like random spots…
Last, there is very little stuff on the ground, if you go outside you’d be suprised how much stuff can be at that level, especially when plant life is thin enough for stuff to fall through… one easy thing to add is little groups of pebbles, just make little low poly mis-shapen spheres with a similar texture to the ground and just place them around, maybe around the closer grass’s bases (again hiding the seam between ground and grass)… also I like the dead flower that you have there… I’d say add maybe a twig or two too and maybe a leaf here or there…
Sorry if all my crits seem like you have bad work, but I’m just trying to make the picture better… one thing you might want to try for materials is google images, just lookup whatever you need like “grass” or “sand” or “dirt” save the picture, put it in gimp, and have gimp figure out the exact ratio of red green and blue…
The spider is great, the only thing I find odd about him are the hairs on his leg, but otherwise it’s grrrrrrrrreat…
For lighting, use only one sun lamp, and use that one sun lamp as the only shadow caster, everything else should be defuse only… usually you want a few lamps around the centerpiece (spider) to accent it… if you go to the www.blender3d.org site, in their tutorial section there should be a tutorial on lighting…
good luck 
PS: now that I look at it a little bit more, the grass might be find in color and it just seems brighter because of the ground, so fix the ground first and make sure 