You can put chests on the first level of the mines and keep stuff there to help you empty your bags or if you need food and such.

You can actually put furniture in a lot of places but if you accidentally put something in the middle of a NPC's path that will be removed (I think in the case of the chest the items inside are lost forever).

Some crops sometimes can grow to be very big if they are planted in 4x4.

Watch the TV every morning. It can help you adapt what you might do that day depending on your luck and weather. You can also get recipes.