The Office of the U.S. Trade Representative produces an annual National Trade Estimate Report on Foreign Trade Barriers . Read the chapter on your target country.
Also consider the advantages of trading with Free Trade Agreement (FTA) partner countries which can reduce tariffs and protect intellectual property rights. Visit the ITA's Free Trade Agreements Help Center and use their FTA Tariff Tool.
This 2 minute video from Trade.gov outlines the advantages of doing businses with FTAs countries.
To calculate actual tariff rates you will need to know the HS code for your product. Learn about commodity codes for trade data and how to use the Harmonized system (HS) in Baruch's Research Guide for International Trade Statistics.
Governments can impose public policy regulations that affect trade. Non-tariff barriers to trade can include import licensing, rules of origin, customs valuation, and technical regulations and standards.