hi -

could you provide any more specific information about the trouble you're having with data sufficiency?

there are more methods than you can shake a stick at, so writing about all of them in the space of a single post would be impracticable.

here are some more specific ideas, in case you haven't thought much about the specific source of your DS woes:
* the logical structure of DS problems in general
* how to choose appropriate numbers for DS number-plugging methods
* the most efficient way to progress through the answer choices
* how to handle "yes/no" vs. "value" questions
* guessing / process-of-elimination methods
* DS issues with particular topics (geometry, number properties, etc.)

any of these strike a particular chord with you? (and i certainly hope it's not "all of them"...)