Bisawmi ghadinn nawaiytu min shahri ramadan
I intend to keep the fast for tomorrow in the month of Ramadan
NOTE : There is no reference in Hadith for this dua.
Abu Hurayrah reported that the Prophet (peace and blessings be upon him) said,
Whoever observes fasts during the month of Ramadan out of sincere faith, and hoping to attain Allah’s rewards, then all his past sins will be forgiven. (Al-Bukhari and Muslim)
Rabbi inni lima anzalta ilayya min khairin faqir
“O My Lord! Truly, I am in need of whatever good that You bestow on me!”