It was quite simple, as I had already worked in that company for 2+ years. I'd recommend:
Review SQL fundamentals and practice on real datasets (LeetCode, HackerRank).
Build a portfolio with dashboards or analyses (Kaggle, public datasets).
Practice storytelling with data — turn raw numbers into narratives.
Refresh basic statistics (mean, median, standard deviation, p-value).
Be ready to explain your past projects: problem, data, tools, result, impact.