Hey there,
Great question--I have a feeling it's something a lot of people are thinking about. Unfortunately there's no magic wand (and if we knew *exactly* what to tell you to do in order to get admitted we'd probably be doing something else with that power...) but all top schools are going to be looking for similar things in a profile. As you noted GPA, GMAT, and professional experience are all hugely important. They're looking for a track record of making an impact on the teams and companies you've worked at, promotions, and taking on greater and greater responsibility over the course of your career.
Outside of all that, there looking for what makes you, you. Hobbies, volunteering, side projects that you're passionate about and have a demonstrated long-term commitment to. (It's painfully obvious when someone picks up a volunteer opportunity right as application season begins--while we recommend getting involved in something outside of work, it should be something you're genuinely passionate about and willing to put the effort into.) Stanford's essay specifically asks applications to answer the question of what matters to them and why. If you can answer that for yourself now it might help point you in the right direction!
Best,
Karen