Here's my go...
My sim lives on the 8th floor of an apartment building I built recently. When I saw this challenge I immediately thought of his tiny, empty balcony, and that wonderful view being wasted, so, I decorated it! (I used tips 1, 3, 6, and a little bit of 4)
My sim, Henry, wanted to be able to host people outside, and to do this he needed a new couch, egg chair, nectar bar, small table, and a couple of dining chairs. He can eat outside now if he wanted!
Henry also likes to work out, so he quickly moved his exercise machine outside, away from its home pushed against a wall inside.
Finally, Henry likes the urban feel of the city, but he misses all of the plants that are out in the country, and he couldn't have a garden, so he put some hanging pots and plants out there so that he can have a little bit of nature!