There is nothing that anyone other than the IRS can do. Continue to monitor the progress. Have you received any letters from the IRS requesting information and if so did you timely respond to them?
Have you confirmed that your tax return was accepted? https://shop.turbotax.intuit.com/efile/efile_status_lookup.jsp
See this info about the IRS process: https://ttlc.intuit.com/community/taxes/discussion/where-s-my-tax-refund-how-to-check-your-refund-status/00/1243829