> Prove you can prioritise

Of all the PMs I've worked with personally, this has been the single largest problem. A PM that has patience and knows how to pick and stick to the most important thing until it's done is worth their weight in gold. It takes balls, because priorities always seem to change from day to day, management applies pressure to the PMs to get more done than is realistic, and engineers are fickle and perfectionist and usually slower than they predict. I've seen a good PM walk this line, but people who can do it are rare. I'll take someone who really can do the job of prioritizing well over someone who knows a lot any day.