The obvious answers run counter to the IMF's preferences.

1. Stop all capital flight.
2. Exchange control - only proper payments for goods and services to be allowed out.
3. Haircut a high proportion of all high net worths.
4. Tax all people and corporations with a Greek presence on a realistic but substantial part of worldwide income and assets (notably shipowners too). Tax on all assets in Greece. Trusts to be fully transparent or ALL assets confiscated.
5. Charges to foreign businesses to use Greek national assetts like ports and airports.
6. Progressive tax structure. Tax the church. Tax collection with the power of the inquisition and an anti-avoidance policy worthy of the Jesuits. 100% penalties on tax avoidance and evasion - amnesty for teh penalty part (but not the tax avoided or evaded) if voluntary disclosure and payment made NOW.
7. End early retirement.
8. Eye-watering import tax on anything for which there is a non-imported equivalent.
9. Sell off military weapons - the army is useless anyway and it would reduce the threat from fascist colonels.