You'll need some tools and materials: tape, hammer, fencing material, nails, a small ax, a level, chisel, saw, a chalk or pencil marker and gloves. You will also need fence posts, a post-hole digger, wood preservative, paint, dirt or gravel, a tamping rod and some ready-mix concrete.
Mark the bottom third of each fence post. This part will go underground, so soak it overnight in wood preservative. To avoid rot from water accumulation, you might want to round, cap or slant the post heads.
Fence posts usually are placed about six feet apart, but that can vary based on the terrain and purpose of the fence. Mark the territory you want to fence by marking the corners or ends with a chalk or pencil marker. Use the same to draw a line on the ground or soil to indicate the periphery and align the posts. At exactly the point (six feet apart) where you want each post to go, dig a hole by driving in a stake. This has to be measured and executed with much care, because the look and strength of your fence will depend on this.
Put the wooden posts into the ground with the preservative-soaked end under the soil. Use the digger to make the post holes, digging wider toward the bottom to ensure stability. Make sure the posts are level and standing at the same height. Pack around the posts with dirt to ensure they remain in a proper, straight position. Check alignment with a level and prop up each post with stakes to maintain the position. Tamp firmly around the post, then put cement around the post base.
Make a mound of concrete around each post to prevent water from pooling at the base, and tamp the concrete loosely to remove any residual air bubbles that could weaken the mixture. Let the posts and the concrete cure for a week or two before finishing the fence.
Fix two rails at the bottom and top of the posts. To avoid decay due to moisture, set the bottom rails at least a couple of inches above the soil. Make certain that the top and bottom rails are perfectly parallel. The easiest method for attaching the rails is with a lap joint, in which you nail the rail to a side of the post without making any kind of groove.
There are many styles in which you can fashion your fence---basket weave, picket, board etc. The easiest method is the one in which you have a few parallel bars between each pair of posts, perpendicular to the posts. With a little creativity, you can grow shrubbery to cover the gaps between the slats for added privacy. Use two coats of paint on both sides.