As to the complexity level of problems, developers in Microsoft, who deal with coding, are probably taking one of the most challenging jobs in the world. But another engineering role, program manager, is not easier in any sense. Before I explain why, let me illustrate what typical product teams look like.

In the diagram, group manager often runs a team owning individual components or feature areas, say, one spell checker DLL in office; a product unit manager owns a product, say Outlook; while a general manager runs a product family, say Office. One compelling advantage Microsoft possesses is that its products are designed to work together seamlessly. For example, in a recent CIO.com article, 10 Reasons to Use Microsoft Outlook for Your Company's E-Mail, 8 of 10 points is actually about interoperability with other software.

Managers define strategy, Developers write code, testers test code, what do PMs do? Well, it is really hard to define - there is even no consensus within Microsoft. However, one thing is clear – PMs do anything except coding(unless they have to :-) to drive projects meeting strategic goals. Enable right things get done right. Figure out gaps and fill them. The role is something like concrete among brick walls. (cartoons on the right)

If you take a look at PM's position, blocks with black bold border, in the organization hierarchy, you will get the challenges here. PMs are supposed to lead their peers to work towards the right direction.

"You are not my boss. Why do I have to listen to you?"

This question gets down the topic of "Lead without Authority". Before you read along, I have to clarify that I am not a PM expert, but I (0) I've been a PM for quite a while, (1) work with great PMs, (2) learn and try most fundamental things which work well, (3) I faced similar situations for many many times, either in schools, or various organizations. Here is my sharing.

• Charisma. You might be incredibly raw smart – you can optimize an algorithm from O(N*N*N) down to O(logN), or you might be able to design a system of .9999 availability, extremely secure, and super cheap compared with competitors… That doesn't mean you can be a good leader. Instead, many of the best leaders, however, will point to the fact that they were "C" students(From Source). 
• Credibility. It is the key to make people follow you. It works like stock value – hard to build, easy to lose. Be careful of it always. Do right things right. Bring something valuable to the team. Your credibility will accumulate gradually. Do what you say, and say what you mean.
• Consistency. People hated to be randomized. Don't always change directions. Clear goal.
• Partnership mentality. Low ego.
• Help others great. Most influences are indirect. People often complain about "over-managed, but less supported". (Check out photo on the right)
• Lead by showing, not lead by talking only. Get your hands a bit dirty. Leaders should be willing to do anything they tell their reports to do. Show domo, mock UI, prototypes to other when presenting a new way to do things.
• Has sense of people. Most basic thing is How to Win Friends and Influence People. Learn to inspire people. Always be positive in every aspect.
• Communicate. Communicate. Communicate. Listen. Ask questions. You can be introverts, but have to be proactive. Be transparent. Understand your audience – strength, weakness, style, and figure out most effective approaches.
• Relationships enhance communication. Invest time in talking to people interactively. When you need to request advice, an opinion, or a task, you can talk to people from a healthy and positive place.
• Sharpen your vision. Look around. Look ahead. This helps in making sound decisions.
• Start to drive teams with strong pseudo leaders
  • Talk to them especially leaders or submarine leaders, get to know what are their likes/dislikes, Ask: How can I help you guys? Win their support.
  • Build credibility. Bring something invaluable to the team, for example, build up strong relationships with a partner team, present a competitor research report, improve team visibility
  • Before making changes, present it to the leaders in private, say 1on1, to reach rough consensus before it goes public.
  • Help others great. Let them get the credit.
• Conflict Management
  • Focus on goals, not conflicts themselves. Not a question of smart or dumb. 
  • If you can control your emotion well enough, 25% of conflicts will go away.
  • Overwhelming majority of conflicts is just because of perspectives and different values. Try to figure out stories of other people's side. People often come to the same solution when presented same set of information. Use negotiation tips. Keep win-win in mind.
  • In worst case – when you have to resolve unavoidable conflicts, say 5 pies for 10 kids, make sure put a fair decision-making system in place, which is often a engineering way.
• You can reward desired performance even without authority
  • Promotions, raises, bonuses are not in your list, but you can affect them in indirect ways
  • Fame. Complimenting an employee on a job well done at a staff meeting or in front of company officers can be extremely rewarding
  • Increased trust. For example, give top performers the freedom to work in a more self-directed manner.