Two points. First is understanding the Common Reporting Standard which Thailand signed up to last year which is the requirement for all financial institutions in the participating 176 countries to declare an individuals details when requested by the Tax Residents country.
The introduction of the CRS in Thailand affects both individuals and businesses with international financial dealings. Under the CRS, key financial information on account holders, such as their identity, account balance, and interest income, will be automatically exchanged between the Thai Revenue Department (TRD) and tax authorities in other participating countries.
Second is studying the detail of any Double Tax Agreement from your home country has with Thailand and realising that outstanding tax liability you may have in the country you are tax resident.