The grass brush I use... made it using a bunch of tutorials and so on. It's very useful for me and maybe you might benefit from it too
I'm not sure if the settings are saved with the brush, but here they are for in case: (you change these at your brush settings tab, usually on the right of the screen)Shape dynamics:
Angle Jitter - 11%, Control - DirectionScattering:
76%, Control - OffSmooth
CheckedWhen using it
I find it best to set your brush to 60% opacity.EDIT
For those who have older versions of PS and the brush doesn't work, here's the PNG of the brush: [link]
All you have to do is open it in PS, go to Edit > Define brush preset > give it a name and save. Apply the same settings as here above and save it again (you can delete the old one then).
Play around with the settings to see what works for you, but basically these settings will make you grass "flow" in the direction you're drawing. I usually go from left to right, so if I go the other way the grass will be upside down.
It works well for semi-bumpy areas. I'd suggest also drawing a few stray grass blades, especially if the grass is "closer" and bigger - makes it look more real and believable.
For more info on using this brush, check other grass tutorials, or this one I made: [link]
(If the file doesn't download or whatever, let me know)