The specifics will differ depending on what career stage you’re in.
However, a few pieces of advice apply broadly (with different specifics):
Always be learning - Expectations and table stakes are always changing. 15 years ago, paid search was a novelty. 10 years ago, growth marketing didn’t exist as a function. Today, the rise of data means that everyone needs to be able to both analyze data as well as tell stories with it. Don’t ever rest on your laurels and think that the way you learned marketing once is the way it’ll always be. If you do, the new era of marketing will pass you by.
Always start with the customer - Success begins and ends with the customer. Understand your customer inside and out, and they will guide you to the strategy you need.
Be a great storyteller - This is related to being able to incite emotion and action from your customers but also to be able to influence your leadership and cross-functional teams.
Be flexible - Related to the first point, understand that conditions are changing all the time in business. Needs change, and you need to as well
Measure everything - Always be able to tie your work to the business impact it is driving. You will be able to use it for your own career story as well as for credibility and confidence.