Small apartments are the norm when living in a big city like San Francisco or New York. It's funny when a friend moves into a new spot and I go to see it and end up describing a 1 bedroom, ~600 sq. ft. apartment as "huge." I really have to take a step back and laugh at myself. But that's just how it is in San Francisco! This is the necessary evil that you must live with to choose life in the city... and it's so worth it! Although our apartments are small, the size issue isn't all evil.
Small living spaces pose their upsides as well. For example, something I benefit from is that it gets me out and about more often, which means seeing friends, exploring the city, new restaurants and bars, etc. You can't really "host" too many people, so you're forced to explore! I think that's great. Another way I benefit from living in a small space is that it's less expensive to decorate it. More money in my pocket to eat, drink, travel, etc. Finally, I love how cozy and minimalist my little jr. one bedroom apartment is. I'm very particular about ambiance. Whether it's a restaurant, coffee shop, bedroom, etc., I don't like to stay in places with a bad ambiance for extended periods of time. I pick the coffee shops I'll work from based on lighting, decor, or workspace -- all things ambiance related. You should feel the same about your apartment. If you're going to be spending the time in there, it's worth it to make sure you feel great about being in it!
Below you'll find my advice that I've used to decorate my own tiny apartment, which I think helps to most efficiently utilize your (limited) space!
1. STORAGE, STORAGE, STORAGE.
This is probably the most important piece of the post. It's best to find things that kill two birds with one stone! (Please don't really kill any birds with any stones!!) So, many things in my apartment have two uses: fashion and function! (Read more about fashion and function in terms of accessories here.) My favorite item for this is my shelving unit from Ikea.
Shelving Unit: It comes in tons of sizes and colors, and with tons of different bins that fit perfectly in them. I put my swim suits, electronic cords, scarfs, medicine, etc. in them. A place to both store all this stuff AND separate the room to both a living room and bedroom all in one. Not to mention, it looks cute!