Recite anytime a 4 units Salat, in each unit (Rak’at) after Surah-al-Hamd recite 50 times Surah-at-Tawheed.
Holy Prophet Muhammad al Mustafā (saws) said "If a person recites this in the month of Sha’ban and then during death his spirit will be removed with ease, and his grave will become spacious, and on the day of Qiyamat when he comes out of his grave, his face will be shining bright like a full moon and ‘Kalmae Shahadat’ will be on his lips."