ROLLING SHUTTER: Set Filtering to "Extreme"

Under the Advanced tab in the timeline in AE, set "Filtering" to "Extreme" instead of normal.  Previews will be excruciatingly slow, but you get the best results on output.

MOCHA PRO: Localize Tracks

I've noticed that when tracking a shot, it's better to localize your tracks rather than trying to find a global solution.  This is probably due to lens distortion etc that throws off the solve, but in a pinch it's a great way to get the data you need and move on to the next shot.

MOCHA PRO: Angle and Zoom

For shots that have quite a bit of rotation and parallax, bumping up Angle to 5 degrees and Zoom to 5% solved the issue of the plane slipping for me.  Of course, mileage will vary depending on the shot.  Downside, it bumps up calculation time almost 2-3x.  Worth it though.

MOCHA PRO: Search Area

I was having wildly incorrect results tracking a grass surface for line removal work, until I unchecked the "Auto" search area feature and entered my own values.  The shot exhibited more horizontal movement than vertical, so dialed in 100 horizontal and 50 vertical.  Worked like a charm.