Four bar linkage
An thorough understanding of four bar linkages will take much of the guess work out of designing a suspension geometry that will meet specific goals in regards to camber, toe, and scrub change with wheel travel.
If no change is required, one option (and so far the only known option) is to make links opposite each other (I.E. the top and bottom are opposite and the left and right are opposite) equal to each other. The angles relative to each other are unimportant.