Court-approved, pattern interrogatories are now very common. Generally, they cover the basics very well, and your opponent will not be allowed to interpose baseless objections in an attempt to slow down the case.
How should you proceed when the court's pattern interrogatories don't fit a cause of action? It's often advisable to bore in on the things you really want. You should always ask about "persons with knowledge," trial witnesses and experts. But beyond that, think twice before you cough up thirty interrogatories that include a laundry list of every idea you have about the case.
By serving narrowly-tailored, highly-relevant interrogatories, you'll have a much easier time overcoming any objections filed by your opponent. In addition, it will force you to think harder about what you are trying to accomplish with your initial round of discovery.
For more about interrogatories, see Illinois Rule 213. Coming up tomorrow: Drafting the "Persons with Knowledge" Interrogatory.