Shoes It's polite to remove footwear before entering a home (or indeed many hostels and guesthouses).
Dress If entering a mosque or church, both sexes should cover legs and shoulders. In mosques women should loosely cover their hair with a scarf (usually provided). In a synagogue it's the men who should cover their head. In churches, men should remove their hats.
Coffee Drinking a cup of coffee with someone is an important preamble before embarking on any important discussion.
Smoking Considered acceptable almost anywhere.
Bosnian Politics Despite the horrors of recent history, many locals are keen to talk about the war era and what's happened since, but it's generally better to listen than to opine.