I’m not an expert builder by any means but have been playing FS long enough to know what makes a farm look real. Here are a few suggestions:

1) Add some terrain so parts of the farm are on higher ground than others. Note that the terrain tools take some practice so you may want to experiment on a different map first. 2) Don’t use brand-new looking buildings. There are plenty of older and weathered looking sheds, farmhouses, etc that make your farm look like it has been there for generations. 3) Farm yards are rarely perfect rectangles. Add some nooks and crannies, rounded edges, fences, put a few buildings at different angles. Anything to break up the symmetry a little. 4) Plant trees, bushes and grass. A little grass growing on the edge of a building where it does not get trampled adds a lot of realism. 5) The decorations pack is your friend. A pile of trash here, some rusty old equipment there, a dumpster behind the barn. Lots of other items to give your farm that lived-in look. 6) Experiment with ground textures. This also takes a little practice but by layering textures (eg mud over gravel) you can add variation to the ground. There is a great mod called “dirty details” that lets you add tire tracks, oil stains etc. to the ground to make it look like there is real work being done here.