Difference between performing Fard and Sunnah prayer

A four rakaat fard prayer consists of: - Takbeer, sana - Two times Fatiha and a Surah - Atehyat - Two more times Fatiha (without aayah) - Atehyaat, Durood and prayer (Rab-ee-Jaalnee...) Is there any difference when performing sunnah prayers or nafils? Is durood also included in sunnah? and are last two rakaats read with only Surah Fatiha or an aayah needs to be recited after Fatiha during sunnah? Are there any other differences between performing sunnah and fard prayers?