Project managers are made, not born. No-one looks at their children and says, "She's going to make a great project manager when she leaves school."
In my time, I have worked with some really good project managers (and some bad ones, too). I have also managed the occasional project, myself. So here are my casual observations about what makes a good PM.
1. Practice your ability to assess and re-assess priorities
I have watched as huge projects veer totally off course, due to poor reaction to changing circumstances and managers blindly sticking to obsolete priorities despite spiralling costs and no progress. Learn a methodology for prioritisation, and learn to spot the tell-tale signs that the goalposts are changing. If it's a large project, build milestones in your project plan to check prioritisation.
2. Questioning skills
Learn to ask questions in an open, constructive and non-judgemental way. Then shut up and listen. If you don't believe what they are saying, do not let that show in your behaviours. Building trust is important, and holding your own council will help you to achieve that.
You have heard the phrase, "knowledge is power." Be open and honest with your sharing of information in all of your dealings. Knowledge is not a weapon. It is not a way to tell everyone how clever you are, either. People are smart enough to know when this is happening, and will not want to help you. Use plain English and use technical terms and acronyms only when necessary.
4. Plan and schedule your communication appropriately
During complex projects, people want to make sure that everything is communicated. They may spend some time planning what they are going to say, and how they are going to present to you. So be consistent. Set a schedule for communications and stick to it. Don't keep badgering people for unscheduled updates.
5. Keep an eye on progress
If you can find a way of checking actual progress yourself, it is useful to do so. If a document needs to be sent, make sure you are copied into it. Look for evidence that tasks are being carried out. The buck stops with you!
6. Be confident, mature and friendly
Everyone on the project looks to you for inspiration. So inspire a sense of confidence in people. Re frame the work as an exciting challenge, and problems as being interesting. Allow people to share their concerns, and give appropriate emotional support. You will get much more out of people when you are on their side.