Many good, solid responses to your obvious question. Is your real question, "What does it take for me to become a top 10% ranked sales professional", or "What should I be looking for when I hire a sales professional (and I want a top 10%er)?"
Several elements for your consideration:
If your intention is to make you a better salesperson-
-The power of a founder counts for A LOT for credibility, and ability to do a deal
-To Dan's points, buyer and value clarity; understanding who buys, how, and why; the evidence they need to proceed
-To Alistair's point, qualification - your ability to quickly and accurately assess prospect readiness and fit is critical
If your intention is to hire a strong sales professional so that you can focus on building your company, validate your business model, and then hire to scale ( that is, if you're building a company v a lifestyle biz)
-As soon as possible, (if you have strong PFM and clearly definable and accepted value props) understand the dimensions of complexity, consistency, competition and cycle. Those are the drivers that establish the type of talent you'll need (dilgence, intellect, poise, grit, curiousity, athleticism, etc).
-If you have a high consistency in prospects, hire for diligence and execution (Dan's points)
-If you have a high variability in prospects, hire for agility and curiousity (Richard's point), and as soon as possible, ID your segments so you can scale by hiring for prospect/segment consistency