The best way to prime colleagues for backing you and your agenda is to make them feel heard. 

Start by giving them your undivided attention in one-on-one situations. Turn your body toward the other person, freeze in place, and listen.

• Your body language is critical to conveying the right message: signal that you are a friend by keeping your arms uncrossed, your hands by your sides, and your torso open and pointed at the other person.
• Pitch your voice a little lower than you normally do in order to connote power. This is useful to work on because it counteracts the effect of nervousness, which tends to push your tone higher.

Increase your influence at work by being seen as a recognized expert within your industry or organization.

This won’t happen overnight, but immerse yourself in your topic area”by regularly attending industry conferences, enrolling in a class or specialized certification program, or taking on a leadership role in a relevant professional organization - visible signs that you are informed and up-to-date.

...when it comes time to leverage the influence you’ve built to promote a particular initiative or idea.

Create a power map, an org chart of decision makers related to your issue,she says. As you go through the levels, “ask yourself, ‘Can I influence this person directly? If not, whom can I influence who can influence that person?’ Then begin to think about how and when you will approach these various colleagues. 

You can increase your influence on a particular issue by authentically framing it as a benefit to the people you want on your side.

Consider each stakeholder’s needs, perspectives, and temperaments. Do your homework to find out what they need to hear and what will capture their attention.