If you have two Murata Electronics Oy's inclinometers on a PCB which are perpendicular to each other, you can compare both of their outputs when tilting them one axis at the time. The other axis' sensor is a control sensor. The change in the output of the control sensor indicates the cross-axis error. The compensation is easiest to do by testing different mounting positions of sensors and trying to find the best position where the cross-axis effect is as small as possible.
For more information on cross axis compensation methods, please see our Application Note 32PDF (PDF: 125KB)