The detectives often discuss elements of their cases openly in front of people who they have just questioned. This would not occur in real life as they would risk having the person who overheard them potentially contact someone who might be a suspect.
When the detectives are interviewing someone or working a crime scene, they are never seen taking notes. Real detectives are constantly taking notes. The notes are so important that they are occasionally booked into evidence to ensure the originals will be available for review before trial.
The time-lines of trials seem to be rushed and take place within days of the crime. Most of the cases on this series are homicides and these cases, if not plea bargained, are seldom heard in less than a year after the event.
In real life, the same group of police officers working with the same group of prosecutors in one year is highly unlikely. Also the same could be said of the police and prosecutors getting through the number of cases they are shown to in a year's time-frame.
When the detectives want to "bring in" or "pick up" someone for questioning, the subjects are usually located instantly. That might work if they had a consistent schedule they followed faithfully every day, but there are few people who do that. Also, many of the people they are looking for are homeless or otherwise itinerant, and even they don't know where they will be tomorrow.
During a number of episodes which portray trials which extend over a multi-day time periods, the jury is often shown wearing the same clothing as during the beginning of those trials.