To do well in this part, you should know the various parts of speech and how they are used to form a grammatically correct sentence. In particular, you must be careful of:

Two-part phrasal verbs
Incorrect use of prepositions
Incorrectly placed adjectives
Incorrect word forms
Incorrect grammatical tense
Incorrect transition word such as however, furthermore, etc.
Incorrect conjunctions such as and, but, etc

Many choices may seem close until you try them out, so to save time, try to identify the grammatical function of the word in the blank.