Hi Irma - I am not a financial analyst but I have a minor in supply chain so I took several business classes in college. From my experience at school and now in a corporate work environment, I would say both know how and personality are important for this career path.
- Know your stuff - go to college and get a degree in Finance or Accounting depending on what you would like to do
- Practice your speaking skills any chance you get (both formal and informal speaking) - a lot of times how well you 'sell' an idea is almost more important than the idea itself. If you are confident and cool under pressure you will have more success in getting people on board with your idea/position/argument.
- Know your audience - understanding your audience will allow you to tailor your findings to how they best communicate, again helping you be more successful in whatever it is you are working on
I hope someone with more experience comes by and gives this answer a go, but I think the main takeaway from my comment is that there is no single 'key' to being a successful financial analyst. You need to be able to do both the numbers side and the people side of the business to stand out.