This last summer my wife and I replaced our sorry looking chain link fence. We used 6×6’s for the posts and the retaining walls. The posts were inserted in fence post protectors to keep moisture off the wood, and to make it easier to replace the posts in the future. Two to Three bags of Quikrete were poured around the base of each post. This brand of Quikrete can be poured in dry and then watered (so no premixing which saves the back).
We chose to frame in hog panel fencing because we liked the look and this still allowed a lot of light to reach the grass. I highly recommend either using a large cable cutter or an angle grinder to cut the panels to length.
To assemble the fence panels, pocket holes were drilled at the end of each of the horizontal 2×4’s and screwed to the 6×6 posts. I prefer this approach because it makes fence assembly (and, if need be, disassembly) very straight forward for one person.
Lastly, we applied two coats of stain (Sikken Cetal SRD, Teak 085) to protect the wood and make the fence stand out.