Texas Instruments recommends a 4-layer PCB with a solid ground plane, and to keep analog and digital signals separate. Also, use short and direct traces for the analog inputs and references.
Use a low-pass filter at the input, and consider using a shielded enclosure. Also, ensure that the analog and digital grounds are connected at a single point, and use a common mode choke to reduce noise.
The maximum sampling rate of the ADS1258IRTCT is 30 kSPS. However, this can be increased to 50 kSPS by using the device's turbo mode.
The ADS1258IRTCT has an internal calibration mechanism. Apply a known input voltage, and then use the device's calibration registers to adjust the gain and offset. Refer to the datasheet for the calibration procedure.
The power consumption of the ADS1258IRTCT varies depending on the sampling rate and operating mode. Typically, it consumes around 15 mW at 30 kSPS, and up to 30 mW in turbo mode.