Each checklist item should stand on its own. You should be able to check any item without having completed another item first.
When items depend on each other, your checklist becomes fragile. If you skip one item, dependent items become meaningless.
For example, avoid sequences like "Step 1: Open the file" followed by "Step 2: Verify the file contents." These are procedural steps, not independent checks.
Instead, write items that can be verified independently: "Configuration file contains all required fields" and "Configuration values are within acceptable ranges."
Independent items make your checklist more flexible. You can check items in any order, which is especially valuable when different people handle different parts of a process.
This also makes it easier to skip non-applicable items without breaking the rest of your checklist.
However, sometimes we actually need checklist items with step 1, step 2, step 3, and so on.
References
Scriven, M. (2000). The logic and methodology of checklists.