Just curious to know, why did you lose your previous client? I lost one of my client several days back as he didn't know actually what to do with adwords. I created one campaign and several ad groups, asked him to create some landing pages from the developer but he said just to notify him when campaign seemed ready. I notified, he paid and flew off!
We don't know the real reason why he left. In my case, I lose one of my clients for personal reasons. Our campaign was running smoothly that time and puzzled when he left. The only thing we can do is move on.