Respect isn't earned. You receive the amount of respect you give.
Every time you interact with someone you should give them a base level of respect. How they respond determines the amount of respect you continue to proceed with.
IMHO a base level of respect should always be given. This base level is earned by existing as a being with thoughts and emotions. The way a person acts, any social standing, etc. can then lead to additional respect on top of that, but the level cannot fall below the base.
I also believe that in a first interaction with a person, you should start at the base level always, regardless of any prior knowledge about social standing etc. This also helps to define the base level in a meaningful way, e.g. if this is the level of respect I award my new boss, this is also the level of respect I should award a random homeless person