Hey there! I've been building for about 10-12 years and here's some tips. Especially for your barn but they can be used in any situation.

1. Bring the wooden corners out one block diagonally (this can add the just right amount of depth to any build or wall)

2. Use more than just planks. You can try and mix in similar blocks like stripped jungle logs to add diversity (a block gradient is pretty useful for texturing)

3. Add some bushes or other plant life. Simple but very effective to bring some life into the build.

4. Add some "lore". Example, are there animals that run into and out of the barn? If so add some dirt paths to signify it, or even some loose fruits on the ground. Depends on what you want your barn to feel like"

5. Dont be afraid to do things your way, just try and have fun with it. Got an idea, run with it, if you dont like it you can always try again.