Open new document (Control + N) Pick a Brush Tool (B)and draw an image like a grass. It's not exactly a like a grass. just.. Brush. Here i use a duller color so when you dodge it become more vibrant
Use Burn Tool (O) to make a shadow at there in the bottom
Now. Highlight the top it with Dodge Tool (O). Remember to set it to Midtones
Smudge the grass (R) with pressure within 70 - 80 depend on realism. smoothly drag you grass upper to make it more real. It will take a little bit time to done it.
Now Dodge it with Highlight setting. Dodge it at the middle area at the grass. Try to minimize the use of this tool. If you use too much it will become worst.
Again, use a Smudge Tool but with a tool size around 9 to make a grass more real and small. Yeah!!