Does anyone have any suggestions or tips for me? I've been playing for like 7 yrs, and I've literally never really designed or decorated my farm or even completed the game, and I really wanna do it at least one of those this year, and I really don't just wanna copy and paste someone else's design, so any help would be appreciated.

I suggest you focus on particalit first, and then try to decorate around that!
For example defiently put your crafting area, totems and the shipping bin clouser to your house!
I see youre allso planning on a drying shed? try to plant some trees and the mushrom logs between them!
Allso furances dont need a entire shed, i usualy have like 5 early-mid game
Grass can be plant on grass (green tiles) but doesnt grow on it. As to be on soil (tan tiles) to grow.