For making it a little bit more organic add a "Noise" modifier to the plane. The value depends on the size of your plane, so just tweak them until they look right. Don't make it to extreme because that will make things more diffecult in the later steps and also needs to be done in a different way. More about that at the end.
Select the grass shaft. Now select the plane to be the "Distribution Object" for the grass, this button is just at the top of the scatter object. Set "Duplicates" to 100. You maybe need to adjust the scale as well depending on the size of your plane/grass. Uncheck "Perpendicular" and set the distribute type to "Area"
Go and change the "Rotation" to X: 10 Y: 784 Z: 10. Y is the shafts Z axis so keep that value quite high and irregular to have more natural results. Change "Scaling" to 10x10x10 and set "Lock Aspect Ratio". Under display options set "Display" to 5%, this will hide 95% of your grass in the viewport, so you'll have faster feedback. Check "Hide Distribution Object", this will hide the extra copy of the plane which was created by the scatter object it self. Scroll up and set "Duplicates" to 5000.
Next step: Animating. Add a "Volume Select" to your grass object and set it to "Vertex", go into sub-object mode and move the gizmo up so it's only selecting the top vertices. Turn on "Use Soft Selection" and change the "Falloff" so that all but the bottom vertices get selected. There is a slight color change that indicates if a vertice is selected or not, dark blue mean it's still selected, then it will change to a brighter blue, which means that it isn't inside the falloff range anymore. This is very important since in the next step we will apply another modifier which will use this selection to animate the vertices. If this is not set up correctly the grass will start shifting at the bottom.
After you're done with tweaking the soft selection add a "Wave" modifier on top of it and set it to "Amplitude 1&2": 5.0, "Wave Length": 35.0 and animate the "Phase" by setting a key at frame 100, value 3 or 4. Also go into sub-object mode and rotate the gizmo by 90 degrees to have the gizmo's deformed side in the Z direction other wise it will deform the grass in the wrong way. Again these values depend on the size of your object.
Make a copy of the wave modifier and add it on top again. Change the values like this for example; "Amplitude 1&2": 3.0, "Wave Length": 50.0 set the "Phase" value lower like 2.0 or 1.0 This will give a secondary animation to it and will vary the result a little. You could also go and rotate the gizmos to add even more variety. To add some small movement for the blades use a "Noise" modifier and set it to: check "Fractal", set "Strength" X: 6.0 Y: 4.0 Z: 6.0 and check "Animate Noise". Again, the values are depending on your object's scale.
That's it actually, now all you need to do is tweak the settings to get the result you want.
For surfaces with grass that are not planar you need to use "Object" for the volume select, make a copy of the surface you want the grass to be on, collapse it, add a "Optimize" modifier with a high value and use "Solidify" it will extrude the surface along it's normals to give it volume. Solidify is a freeware pluging that you can find here: http://www.maxplugins.de/
. Use this new mesh the same way you did with the original box gizmo. Another important thing is that scatter can only make a maximum amount of 65.000 duplicates, so if you need more simply make a copy of your grass object and change the seed value. How ever this technique is very memory intensive when using hugh amounts of grass as well as takes quite some time to render. You should not use this in big scenes if you have less then 1Gb of memory.