Yes, Watch Mashiro Symphony first, It's light compared to some of the otehr stuff and an easy watch that doesn't take up a ton of time and is easily enjoyable. I would follow it up with Rosario and Kanokon (It's actually Kanokon, not -ken). I would save Shuffle for later on, it can be hard to watch near the end, no spoilers but you need to have a strong stomach to finish it off.
You can't spell sLAUGHTER without LAUGHTER
~I am the Emperor of Carnage~