Creating grass
My first real challange came when it came to making foliage. I had absolutely no idea how i might do this. However after a day of trial-and-error i made a grass mesh by modeling low-poly blades of grass, and duplicating them with the hair particle system in Blender.
Creating leaves
My woods were looking kind of barren without any leaves on the trees, so i had to fix this ASAP. So what i did was open up the best 2d-image editing software of all time, Paint.NET (/s). First i downloaded a transparent leaf texture, and then stylized it by altering the color and adding a crystalize effect.
After adding planes with my new leaf material to the trees, the end result looked like this: