At Castlight Health, I am focusing initially on execution, product goals, training and development for my colleagues and product design in that order.
I find that looking at simple foundational things that need to be done is an important first step. If there is a lack of ability to execute, that area needs to be attended to first. This usually boils down to everyone knowing their goals and knowing who does what when to accomplish those goals.
The next things I am focusing on is to find out if the right people are on the right job and if they needs any specific skills. Putting the right people on the right job and getting them the necessary training is the important next step. This includes hiring.
The next area is the design of the products that I and my team are responsible for. Even though this is what I love to do, this cannot be done if the first two things are not taken care of.
You might be wondering why I did not mention the word strategy anywhere. I believe that it is hard to change the strategy of a product area until you have gained the trust of your colleagues. I plan to focus on that after the first 90 days. Also, I believe that it is harder to execute on a strategy than to come up with one.