If you are looking to add some privacy for your deck you may want to consider installing a privacy fence. Most privacy fences are about 6' tall and are built from wood or low maintenance vinyl. Securely attach 4x4 fence support posts to the deck rim with (2) 1/2" bolts with washers just like a rail post. You should space the posts between 4' to 6' apart. Then you can attach a 2x4 along the top and bottom of the fence with a couple of 3-1/2" wood screws. The next step is to stagger the 1x6 fence boards to either side of the 2x4 and attach with 2 nails for each fence board. Many fence boards are made from rough sawn material and some are dog eared. Make sure the material is clean, straight, and free from loose or empty knots. Staining rough sawn material will require a lot of extra stain.
Some builders install a decorative top to the fence using lattice or short aluminum balusters. This can be very simple or elaborate. Your preference will determine the composition. The decorative fence top is usually installed across the top 12"-16" of the fence. This will allow you to add some variation to the design and allow some light to penetrate the top of the fence. You may want to run a 2x6 over the entire top of the fence to cap it off or install decorative post caps.