In negotiations many people try to get things for them, cause it seems obvious. They don’t spend time figuring out what facts the other side have about them. You can’t force them into agreement if they think you don’t deserve this option. It is never good enough that only you believe you deserve it. It has to be clear and believable also to them.
Building authority is not bragging. You just start negotiations with saying few things about you which are important during those talks. You want to state your experience and say the facts, which they might not know.
You should never ask for something without giving a good explanation of why you deserve it and why it make sense for you to ask for it. It’s a special technique which you can use stating those things. Using the word because after stating your demand can increase positive answer by 93% according to Cialdini research in Psychology of Persuasion. The word “because” is used to justify a request that was just made. By giving an explanation to someone, they will try to understand you and conemplate as to whether your reasoning is balid. This also helps to get to know you on a more personal level, making them more willing automatically to do something for you. If they think exactly like you, they like you more and this gives you an advantage.
It’s always important to fight for what you deserve, however you should do it in less emotional way. Keep in mind that those people should like you at least a little at the end of the day. Without it, they might agree now, but later they would not do the things you asked for. You have to see the line between promoting yourself and coming off as arrogant.