Excel at Selling Excel at Selling is a licensed centre for DEI Sales Training based in Dublin. We work with companies to grow their business by developing their sales teams. We believe that selling is first about sales process management and not about "how to sell". With an effective sales process in place – that evaluates real sales opportunities – you can add proven sales techniques and skills. DEI is known for its honest, practical, simple and intelligent approach to managing the sales process and selling technique. DEI Sales Training DEI sales training was set up in 1979 by Stephan Schiffman. Over the past 30 years, 500,000 salespeople and 9,000 companies have used the system to consistently develop new business and predictably hit their sales targets. Ours is a proven, simple and intelligent sales process that actually works. We work with sales teams, managers and owners all over Ireland in all sectors; manufacturing, software, services, financial, media, pharma and medical.