How do you parse a sentence? For example, parse this sentence: "When I married my wife, she was a teacher, but she later became an accountant...

When you parse a sentence, you are examining the grammatical construction of the words the sentence contains, naming the parts, and describing how the parts relate to each other. The first step is to find all the verbs in the sentence, making sure to find all auxiliary verbs and forms of the verb "to be." In this sentence, the verbs are: married, was, became, took. Verbs can help you find out how many clauses you have. In this case, the four verbs belong to four separate clauses.

Next you can identify which clauses are subordinate (dependent) and which are independent. An independent clause can stand on its own as a sentence; it has its own subject and verb and it does not begin with a "clausal starter" word, or subordinating conjunction. Here we have two independent clauses: "she was a teacher," and "she later became an accountant."

The other two clauses are subordinate because they begin with the clausal starters "when" and "after." 

Within each clause find the basic constituents, the subject-verb-object arrangement. For example, in the first clause, the subject is "I," the verb is "married," and the object is "wife." 

This may be the extent of parsing you need to do, or you may want to identify each individual word as a part of speech. You would label each word as a noun, pronoun, verb, adjective, adverb, preposition, conjunction, or interjection. For example, "my" is a pronoun, "later" is an adverb.