Walk along the line where you will be installing your new fence. Drive a stake into the ground at 6- to 8-foot intervals to mark your post holes. The distance between each post depends on the weight of the wood you will be using and your local weather.
Dig a hole with a depth equal to one-third of your fence posts' length at each staked location. Using a post hole digger will make this process easier, especially if the ground is dry and hard. Pour several inches of gravel or small rocks into each post hole. This will allow water to drain so the bottom of the post does not rot.
Insert a fence post into the hole at one end of your fence line. Fill the hole with quick-dry cement to hold it in place. Use a level to make sure your posts are straight up and down. Repeat this step to install the post at the other end of the fence line. This will give you two anchor points to use when you install the rest of the posts. Attach a string or piece of twine to each of the end posts. Install the middle posts along this line.
Cut several 2-inch by 4-inch boards to a length equal to twice the distance between each fence post. For example, a fence with posts placed at 6-foot intervals requires 12-foot boards. These boards will be the top rails of your new fence. Lay the rails on top of the fence posts and drive nails into the two end posts and the post in the middle of each rail.
Measure the distance between the inside edges of your fence posts. Cut several 2-inch by 4-inch boards to this length. These boards are the bottom rails of your new fence. Drive two nails at an angle into the top of each rail to anchor the rail against the side of the fence post. Repeat this on the other side of the rail to secure it in place.
Start at one end of the fence and attach the 8-foot pickets with two nails through each rail. Leave a gap of one-quarter to one-half inch between each picket, depending on how much privacy you want.