There are four things to look at when it comes to evaluating a slip and call claim: duty, breach of duty, causation, damages.
Duty: Whomever you are suing must have a duty to maintain safe spaces or prevent hazardous situations or defects from arising that could cause injury. For example, grocery stores have a duty to maintain their aisles from spills or produce to prevent a hazard.
Breach: There must be a breach of this duty. In our example above, it would mean that grocery store employees knew or should have known that there was a spill or something in the aisle and they neglected to clean it up.
Causation: This means that the defect itself caused you to fall and resulted in damages. I.e., it was the liquid in the aisle that should have been mopped up that resulted in your falling on the floor and being injured.
Damages: There must also be resulting damage. If you slipped and fell but were not injured, there is no claim. Damages can be both tangible and intangible losses such as loss of income, medical costs, pain and suffering, and future loss or cost.