Thank you for your question.
To the usual "forms" of various readability that you can find on this here Innerweb, the following are added and deleted from the standard language. Seeing such huge range of useful- to near-useless-ness from the "free" sites, I really have to recommend that you start with something like LegalZoom.com or FindLegalForms.com.
1. Add "LIMITED" to the title.
2. Add "limited" or "Limited" (depending on style, some capitalize the document title everywhere) before every statement of power of attorney or grant of authority.
3. Add a sentence describing the narrow scope of the PoA.
"This Limited Power of Attorney is granted ONLY for the purposes of transacting business with _____ company] located in _______[city], [country] related to my [whatever the type of business deal is contemplated], and extends to no other subjects."
4. IF access to any money is also involved, like writing a check, then as a non-legal matter the funds should be put into a separate dedicated bank account with no other monies. Preferably the money would be deposited with a Cashier's Check, to avoid any fraudsters from tracing the money back to your specific bank account (they usually get no joy if all they know is the issuing bank of the check...so write a short letter to your bank reminding them of you financial privacy rights and alerting them that you will NEVER be communicating with them by phone regarding anything).
It is important to be thorough, to make sure that nothing is accidentally left in there which could be mis-interpreted as a broad grant of a general power of attorney.
And don't make it "durable" unless you REALLY want your agent to take action even if you are in a coma. That's what "durable" is all about. It belongs in estate planning, not in international trade