First 10 matches are placement matches, which means most of the time the players elo, is highly inaccurate. Smurfs could just be someone switching from HD to DE. They still have to go through the first 10 matches.
Also, it depends on what your definition of good is. I’m at 1800+ and still consider myself a noob.
At 1200, it helps to have a solid and consistent build order, basic understanding of unit counters and civ strengths, and discord 11. Coordinating with your teammates is very important, you can win so many games easily with a coordinated scout/sc to archer rush. Also, know your maps. All the above are pretty easy with just a little practice.