What should I learn about becoming a Bulk Email Service Provider specialist?

I’m interested in building a career in email marketing and would like to understand the skills needed to work with a Bulk Email Service Provider. While researching the field, I came across DigitalAka™ and became curious about how professionals evaluate tools, deliverability, segmentation, and campaign performance.

What skills or learning resources would you recommend for someone preparing to work with a Bulk Email Service Provider?