Major differences are:
In their adhan and iqaamah, they say "I bear witness that Ali is the wali of Allah"In their adhan, they add "Come to the best of works" and believe it was removed form Azan by Muaviyeh - whereas according to the Sunni's you only have Come to prayer and Come to success
In their tashahud, they add "And I bear witness that the Amir of the Mu'mineen is Ali, the wali of Allah"In their Salaam, after the tashahud, they add, "Peace be upon you (referencing Ali R.A)"
What they do after the Salah
They praise FatimaThey do Fatima's Tsbihat taught by prophet SAWW (34 Allahu Akbar, 33 Al-Hamdu LeLlah, 33 Subhan Allah). (This is recommended and not obligatory)They say Allahu Akbar 34 times (according to Sunni's this is done 33 times)
They make a sujood of thankfulness as a highly recommended practice after prayer.
They send curses on the enemies of the "infallibles" as a recommended practice.
They do "Ziyaraat" (a short Salam to soul of prophet SAWWProphet (SAWW) and Imams while standing toward direction of their graves)
My answer comes from authentic Shia sourcesMy answer comes from authentic Shia sources