Hi there!
As others have said, don't worry too much about your first SAC. You still have heaps of opportunities to do well in your remaining assessments, and then, of course, the exam! Don't give up on that 50!
I think an important aspect of trends to note is that they tend to occur
over time. That is, for example, saying "men tend to have higher rates of obesity than women" is an observation, whereas "between 1990 and 2014, the rate of smoking in adult males has decreased" (I'm not actually sure if that is true or not, but it is immaterial) is a trend. It's even better (and highly preferable) if you use specific data from information that you are given. It is a data analysis, after all!
Best of luck and kind regards.