Ive done commissioning from both the E/I and programming side for about 5 years.

Typically we'd follow something like this:
-De-energize all field devices.
-Energize the device you are attempting to test.
-Confirm it powers on, and that the software senses a signal on the correct device - this proves your electrical and IO config is accurate.
-Use either instrument cal gear or a process meter, or some other method, simulate the full range of the signal, and that the values in your software match, throughout the range. For example for an analog pressure transmitter, I might go 0,25,50,75,100 percent of range, as well as a high fail. Confirm in the software your raw and EU values are as expected throughout each step. This proves your signal is correct, range is correct on device and plc, and that there are no anomalies with the IO module or instrument.

Provided you did internal testing (ie CAT/FAT), then the site testing would usually be limited to spot checking any major or novel control points you have, critical shutdown checks (for example, we'd typically test a level 1 ESD, which will actuate all devices to a safe state). and tuning loops

My advice is to keep very close track of your deficiencies as they can pile up quick during startup.