The rules for the capitalization of job titles depend on the order of the words, the use of the words, and whether or not the job title is part of the person’s name. Following are explanations and examples.

The easiest rule to remember is: capitalize a job title that comes before the person’s name. Example would be: Professor Plum or Reverend Green. The title might give more information, like: Dean of Students Harry Houdini, Speaker of the House Thomas Thumb, or Chairman Scarlett.
Also, if the job title comes right after the person’s name then it is capitalized, as in: Sarah Smith, Chairman, will attend the meeting. In signature lines, the job title would be capitalized, like:
Sincerely,
Mary Contrary, President
If a job title is not preceded or followed by a person’s name, it may still be capitalized, if it is used as a name. For example: “I saw the Prime Minister today.” In this case, it is being used as name and not a general kind of job, as in “We have had eleven prime ministers in this century.”
To summarize the capitalization of job titles, you capitalize the job title when it comes immediately before the name or immediately after the name. It is not capitalized if it comes after the name if there is a “the” before it. Here are some examples of these rules in sentences:
Another rule of capitalization of job titles concerns abbreviations. Doctor Seuss would be Dr. Seuss and General Grant would be Gen. Grant. So the rule could be: capitalize job titles or abbreviations that come immediately before or after a person’s name.
Here is a summary of the general rules of capitalization. First will be an explanation of things that need to be capitalized, then there will be a short list of things that should not be capitalized.
Capitalize:
Always capitalize the beginning word in a sentence, a line of poetry, or the beginning of a quote. Last but not least, always capitalize the pronoun “I”.
Do not capitalize things that are being referred to in general, like:
Proper nouns name a specific person, object, event, place or idea. They are always capitalized. Here are some examples by type:
Common nouns refer to things, people, places, and ideas in general. They are not capitalized. It is easy to think of objects, people, and places; but sometimes it is hard to think of ideas. Here is a short list: humility, despair, love, poverty, honor, hope, curiosity, fear, grace, liberty, skill, intelligence, slavery, and peace.
The sun, earth, and moon, are not capitalized unless they are part of a list of planets and celestial bodies. It is correct to say, “The moon is full.” and “The inner planets are Mercury, Venus, Earth, and Mars.
Fall, winter, spring, and summer are not capitalized unless they are part of a name. For example, Winter Solstice is a name so it is capitalized.
When using the words god or goddesses as mythological deities, they are not capitalized. For example, “The god Zeus was the god of lightning.”