Spiritually speaking, how does one respect a person, without respecting that person's belief?

You treat them with politeness and avoid being a scoffer or taunting or teasing.  You treat them with dignity.  The same kind of dignity you want for yourself.  They may be wrong in their beliefs, according to your own teachings, but you still must be courteous.  Imagine you are hauled before a judge who has the power to destroy your life, like lock you away for the rest of your life.  Your fate depends on being polite to him or her, being humble and obeying the rules of the court.  You don't want to offend that person.  So you must be "instantly in season and out of season" like Paul recommends for reaching people with the gospel.  Notice when Paul went to the city where they worship Diana, he didn't go around scoffing and saying, that's stupid, your god doesn't exist."  No, he pointed to the monument to the Unknown God and told others he knew who that God was.  And politely told them about Him.

A person is created in the image and likeness of God. A person's beliefs are purely his own.

Beliefs are beliefs and can change but most "persons" will not. I don't care what one chooses to believe but I do care about who that person is and "respect" is earned now mandated.

Spiritually speaking, how does one respect a person [ no comma ] without respecting that person's belief?

That depends on which belief you're talking about.

WITH kindness not force.

When I make a  a new acquaintance,  I don't inquire about his spiritualty!  

I respect people who respect others!

That is displayed in a person's behavior.

I care nothing about what he believes! 

Love God with all your heart Love your neighbor as yourself

Treat him with kindness. Agree to disagree.