- Before Birkhat HaMazon, one should fill the third cup of wine, and say Birkhat HaMazon over it. After Birkhat HaMazon, one should recite ha-gefen and drink while leaning.
- One should recite Birkhat HaMazon while holding the cup of wine.
- One shouldn’t recline during Birkat HaMazon rather one should sit up and say it with concentration. 
- In Birkat HaMazon, one should make sure to say Yaaleh VeYavo mentioning Pesach and if one forgets one has to repeat Birkat HaMazon. 
- The fourth cup is filled after Birkhat HaMazon.
- Shulchan Aruch 479:1
- Chazon Ovadia, Haggadah Shel Pesach, p. 99; presumably, this is based on the Shulchan Arukh (183:4) which states that when making Birkhat HaMazon over a cup of wine one should raise the cup a tefach.
- Yalkut Yosef (Moadim pg 409)
- Yalkut Yosef (Moadim pg 410)
- Kitzur Shulchan Aruch 119:9