Most DIY wood fence these days are made of prefabricated panels. The quality of the fencing panels available ranges from the top quality to almost disposable. The manufacture of your own panels puts you in charge of quality control. Get the best of both worlds by selecting the pickets already made in the style of your choice. Horizontal rails manufactured from 2 by 4 treated lumber will add strength to the panels. Use treated cover screws to make the joints stronger.
Attach the horizontal rails for one fence panel at a time. Use two of 8 feet, it was treated 2 by 4 for short fences, up to 4 feet tall, or three for taller fences. Space them with a 6-inch from the top and a 6-inch from the bottom. When using three lanes, place the third lane directly between the top and bottom rails. Position the vertical pickets using a quick square to ensure a certain 90 degree angle. Place the first wave of pickets with the left ends of the horizontal rails.
Position the first panel without associating the pickets to determine the appropriate space using a tape measure. Leave the same distance from the last of pickets on the right side to the end of the rails when coming out from between the pickets. This will create the appropriate space between the end of one panel and the beginning of the next.