BUT my textbook actually instructed to consult Polish people as to the proper way to approach business correspondence TO a Polish business person. The point is to teach us cross cultural communication skills.
Oh the irony!
Poles consistently underestimate (and downplay) cultural differences between themselves and Americans (bunch f reasons for this, none of which do I intend to explain now).
My suggestions (American living in Poland for well over 10 years).
1. Polish people tend to be more hierarchical than Americans, formal titles etc are more important. They also tend to place more importnce on formal (paper) qualificatins than on real world experience with no certificates to back it up.
2. For Americans politeness is based on being friendly and open and breaking down barriers, in Poland being polite means keeping your distance, professionalism means keeping things formal
3. English is not the first language here and even very competent translators might not understand informal usage and might find many idioms you take for granted to be opaque (or misinterpret them)
4. Polish people have more cross cultural experience than most Americans (crucially they have more cross cultural experience where neither side can make the other defer to their norms).
1. Be more formal than you might be comfortable with, use titles (and make it easy for them to use titles back),
2. Use clear, transparent language, try to avoid idioms and spell everything out clearly
3. Don't presume to bear the burden of tolerance all on your own. People in other cultures enjoy being tolerant of outsiders' mistakes too and no Polish business is going to disregard a letter because it uses non-Polish formatting.