This is usually the long, drawn out period of time after Arraignment and before trial, during which the state prosecutor and the defense attorney gather evidence, case law, amend and have motions heard by a judge. Notice requirements and court schedules consume much of the time that client's often think is wasted, particularly if the client is incarcerated. It does take up a lot of time, but it is not wasted.
This is the time when whatever investigation your lawyer plans on doing occurs. Facts, witnesses, document and record of all sorts may come into question as a result of this investigation by your counsel.
Valuable strategy and trial tactics are being formed during this time and hearing on the motions allow the parties to know what will be allowed as evidence in the trial or not. Most of this goes on without the client involvement, often resulting in a client's impatience and confusion and frustration. ( Hint: Sometimes, the state might “lose” a file, so DO NOT make inquiries from the court! Let that sleeping dog lay!)
It is also during this time when negotiations regarding possible plea offers will take place as unavoidable facts are discovered that will help or hinder the case of either side. Unfortunately, many state prosecutors use the tactic of delay in these plea offers. Many such offers come only on the week or even the day of trial.