Keeping detailed records helps a lot in case of witnesses I think. Trials that don't last several years would be great too. Maybe avoid questioning people more

Keeping detailed records helps a lot in case of witnesses I think. Trials that don't last several years would be great too. Maybe avoid questioning people more than once? I don't have a solution or even that much knowledge of how it's already done. I'd say it's easy to point at cases where it obviously works well and where just witnesses without physical evidence are highly problematic. It's the cases in between that are hard. Even Sherlock Holmes always gets a confession in the end. Without a confession the case isn't over. Ever noticed that?