1. As the applicability of TDS depends on type of exp. Take the dump of all expenses GL on about which you think, if exp is booked in this GL, TDS would be applicable.
2. Take out the vendor name from these GL.
3. Ask for the complete dump of Vendors GL with PAN no. with the TDS deducted against each transaction. Format should be like this.
Vendor Name, PAN no., Invoice no., Date of Booking, TDS deducted, section, rate and in remarks column (if any advance is given)
4. Check the details by using excel autofilter facility like filter first by section and check the exp type to ensure TDS is being deducted under correct section and so on
5. Use the above details to check that TDS return is being filed with correct information.
6. Check the acknoledgment.
7. Ask for Consolidated TDS statement to cross check the TDS return.
That is all I could say. But I may have missed something