The correct answer to a text completion question will always maintain the overall flow and meaning of the sentence. To easily detect the flow of a sentence or passage, you'll want to look for key words which indicate a shift in meaning, tone, etc., or which otherwise maintain certain tone and hence imply continuation of a theme.

For example, consider the following sentence:

We were overjoyed by his homecoming; however, we were conscious of the fact that his high strung nature would be the cause of _______ during his visit.

Even before you look at the answer choices, you should note that this sentence is a compound sentence—there are two statements, joined through the use of a semicolon. Most importantly, notice that the second part of the statement begins with the word “however,” which is a contrast word, and so the general tone and meaning of the second part of the sentence should be in contrast to the first. In the first part of the sentence the main idea is that of being overjoyed, which is a positive emotion, and so the second part of the sentence should imply the opposite, as indicated by the use of the contrast word “however.” Possible answer choices for the blank are thus stress, consternation, angst, etc., all of which are roughly opposite in meaning of joy. Only after you have done such analysis should you then proceed to the answer choices.

Words that indicate contrast and indicate shift in flow: however, although, but, despite, on the contrary, yet, on the other hand, surprisingly, unlike, in contrast, rather.

Words that signify support and maintain flow: likewise, furthermore, namely, resembles, for instance, specifically, such as, as for example, like, likewise.

Words that signify a consequence and imply a causal relationship: because, therefore, consequently, thus.

Should you memorize this list of keywords? No, but be cognizant of them. And realize that they can help you to eliminate answer choices that do not sustain the overall flow and meaning of the sentence.