The proper way is straight back to front then cross front to back. However, I usually just rotate them straight back to front and straight front to back because it is easier. I also look at the wear pattern and will cross rotate if needed. It is not very often that I need to cross rotate. If you rotate every 7K to 10K miles and the front end alignment is good, just switching straight front and rear will work well.
There was a time when reversing the rotation direction of the tires (cross rotation) was a bad thing, but not any more.
2002 FX4 Bright Red Supercab 4.0 SOHC, manual 5-spd & Tcase, 33" BFG MTs, K&N air filter, Modified air box inlet, Gibson SS cat. back exhaust, Bama flash, Hidden Hitch round receiver, Rear helper air springs, Electric trailer brake controller, Line-X bed liner, WAAG bar with KC lights and Wildernest shell.