That's especially important because often you'll be the person responsible for the execution and the success of a project and you'll have a team of people who will be doing the work but they won't report into you directly.
Being able to influence is crucial so that your team can follow your guidance and requirements, but it's also important even before you start your project - you need to be able to get stakeholder commitment so that you can get the resources you need for your project and have the buy-in of key people in the organisation that will support you in case of difficulties because you'll need to have convinced them of the importance of your project.
There are typically five strategies for gaining stakeholder commitment. I learned about them from a paper on PMI written by Bill Richardson.
We'll cover them briefly in a second but what I'll also do is to spend time on looking at how these strategies might have to be adapted based on cultural differences.