Knowing how to do programming is a must: Python, R(both are quite popular). Being hands-on with Linux helps as well, as many real-world datasets won’t fit your laptop, so you’ve got to use high-performance computing infrastructure. But it’s mostly about being able to make inferences from data. You need a solid stats background for that.

There’s a ton of courses online and https://www.edx.org/bio/rafael-irizarry is a good start.