Here's what you need to do to make an LD case. I'm not sure what league you're in, so I went with a Stoa example, but you can insert the words of your own LD resolution (which has an X term and a Y term).

1. Determine a fair way to evaluate the two values provided in the resolution. You're looking for a common denominator. This is the primary idea the debater will introduce throughout the season. Many call this concept a value (now we've got 3 meanings of the word value going on).
2. Construct the case as follows:
I. Introduction
II. Resolutional analysis: Z (your weighing mechanism/value/idea/common denominator) is the best way to evaluate the X (truth seeking) and Y (individual privacy) terms given to you by the resolution.
III. The contention: X term of resolution (truth seeking) is better than Y term of the resolution (individual privacy) because it gets more of Z (your proposed common denominator/value metric)
  1. X term of resolution gets a a pile of Z, comprehensively (not anecdotally)
  2. Y term gets some amount of Z as well
  3. Because Y gets less of Z than X does, therefore... X>Y (truth seeking > individual privacy)
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Here are two resources that may help:
1. I have an email list – if you join it, the first email has sample cases!
2. I have a casewriting course right here on Studio Burning Bush