What kind of pattern should I use when laying the planks?

The ideal laying pattern is one that minimizes any kind of repetition.

The pattern should be as random as possible, so seams (or "joints") do not catch the eye.

Two main patterns to avoid are close joints and "H" patterns. The image below shows an example of an install with random joints, and another one with both close joins and "H" patterns:

56c816bca6f8d_installation-pattern

You can easily achieve a nice install without too much effort by simply making sure the first piece you install in each row does not result in a close joint to the row before it (at least 8" apart), and that it doesn't line-up with the joint two rows over. Because all the planks in Modin are the same length, getting the first plank in each row correct will ensure all the following planks line up correctly as well.