Review 401k withholding – you still have time to adjust your 401k contribution amounts for your last few pay checks.
Increase withholding – Prepare a tax projection for 2017. If you estimate that you will owe, you can increase withholdings in your last few pay checks. This will avoid estimated tax penalties as taxes withheld are deemed to be paid evenl over the year even if actually done late in the year.
Review your cafeteria plan and HSA accounts – you still have time to adjust your withholding and plan any required spend down of these accounts.