Thank you for the feedback! I assume you are talking about the orange-yellow grass, which i painted by drawing the individual blades of grass in different colors with a low-opacity pressure sensitive round brush. I made sure to draw over it many times until it blended together nicely. After that I used the photoshop mixer brush tool as a colorless blender just a little bit to reduce the sharpness.

The tree leaves were drawn in a similar method, but using different shaped brushes to give the leaves some texture. I painted all the leaves in one layer, but kept painting over it with different low-opacity brush colors until i got the desired depth and color.

Regarding online tutorials, I would recommend this free website that hosts informative videos about digital artwork: https://www.ctrlpaint.com/getting-started