Managing without authority

Thank you Lawrence for your feedback on this. I appreciate it.

I expected more feedback from you than this Anish LOL.

These are great inputs from the group, fully agree.
How to get ever better as a leader without authority?
My personal story is that I volunteered in a PMI Chapter. I had no formal authority over my fellow volunteers. And they were quite different. Forming a team out of them was a ongoing challenge.
Volunteering gave me a sandbox to improve.

Hey Anish, this is a common situation in Matrix org structure. I completely agree with Kiron's comment - you need to forge positive relationships with functional managers and inspire your team.
Also, I am working with such org and sharing my experience. I have to talk to individuals from different teams on daily basis to get my work done. It is obvious that my project work is kept on hold because some work received from functional managers. I have to be on my toes always and always tracking the project to make sure that the dots are connected.

Make it beneficial for people to work with you and they'll do so gladly. If people hate useless meetings, for example, minimize the number of formal meetings they're involved in and make sure the meetings they attend are well-organized and highly productive. If people desire to learn new skills, make sure you extend to them opportunities to do so; at the very least letting them know you're looking out for such opportunities will probably make them favorably disposed toward you. Each person is different, so you'll have to figure out what they want and try to offer it to them.
With technical people, I find being highly organized and reliable is the best way to make them want to work with me. Technical people tend to hate wasting time, so getting them the resources they need and taking care of problems that hinder them are great ways to earn their favor.