Identifying clue in Text completion

GRE Verbal Problem Solving
1

I am continously struggling with Text Completion. I am unable to guess blanks from clue. I am confused how the clue implies particular guess (without seeing the option at first).

For Example

An investigation that is ________ can occasionally yield new facts, even notable ones, but typically the appearance of such facts is the result of a search in a definite direction.

How can we think that our focus word is “definite direction”.

If someone has some tips then kindly share with me.

2

You gotta think about what the blank describes. Blank here is describing the nature of the “investigation”, so you need to be focused on parts of the sentence that are also about an investigation/search in order to support it.