I'm not really a sales guy. Marketing yes, I love the ideas, creativity, planning, gathering of data to tweak and modify strategy. But sales, not so much.
For me, it's all about getting your shit turned in and working really, really hard doing things that are not scalable (i.e. getting on the phone and feeling the pain). You want it to hurt really bad; you want to just get your ego kicked in so much that when you start to get better and smarter and tougher, you have thicker skin and you're able to truly understand what it is to have a human connection and truly understand what it is to be able to work a conversation and work a sales process.
Understanding the technology is important, but understanding a sales conversation and process from digging deep, reading books, trying new things and having every opportunity to develop leadership and speaking skills. Those are the things that move the needle.