If you’re representing yourself, you likely won’t be doing formal cross-examination the way a trial attorney would — but understanding the basics helps you follow what’s happening and work more effectively with your own attorney if you have one.
The core technique for challenging a witness’s credibility is pointing out inconsistencies between what they say at trial and what they said earlier — in a deposition, a written statement, or another document. An attorney doing this will typically confirm the earlier statement was made under oath, then read the prior statement alongside the new one so the contradiction is clear to the judge.
Cross-examining an expert witness is its own specialized skill — it usually focuses on exposing bias (financial relationships, how often they testify for one side), gaps in their qualifications, or disagreement from other recognized experts in the field. This is genuinely difficult to do well without training, which is one of several reasons to have an attorney if your case involves expert testimony (like a custody evaluator).