A fence is only as good as its posts, so most of the work is in layout and setting. The order is: mark the line, set the posts, then hang the rails and pickets.
Layout and posts
Run a string line between the two end points and mark post locations at 6–8 ft spacing (closer is stronger). Dig each hole about one-third of the post’s above-ground height deep — a 6 ft fence wants roughly 2 ft of post in the ground — and below the frost line in cold climates. Set posts in concrete for the firmest hold, checking each for plumb in two directions before the concrete sets.
Rails and pickets
Once the posts cure, attach horizontal rails (two for fences up to ~5 ft, three for taller), then fasten pickets to the rails. Use a spacer block to keep gaps even, and a string line to keep the tops consistent.
Frequently asked questions
How deep should fence posts go? About one-third of the above-ground height, below the frost line.
How far apart are fence posts? 6–8 ft for wood; closer spacing makes a stiffer fence.
Concrete or gravel? Concrete is strongest; gravel improves drainage in stable, well-drained soil.