Every sincere dua is accepted without a doubt, but we are recommended to package our duas in such a way that if there was even the slightest chance that perhaps our dua was not going to be accepted, then allah will overlook our slips and accept our dua anyway, for far be it for Him to accept part of a dua and reject part of it.
With this in mind, this is how I package my duas
Shaykh al-Saduq, may Allah perfume his tomb, has reported on the authority of ‘Abdullah ibn Sinan that Imam al-Sadiq (‘a) said:
I see coming that a seditious matter shall inflict you, leaving you without visible sign or leader to the true guidance. None will be saved from it except those who say the Supplication of the Drowned (Du’a’ al-Ghariq).
يَا اللّٰهُ يَا رَحْمَانُ يَا رَحِيمُ يَا مُقَلِّبَ الْقُلُوبِ ثَبِّتْ قَلْبِي عَلَى دِينِكَ
The supplication of Fatima al-Zahra (sa) is a highly recommended prayer for obtaining ones demands:
يَا اللّٰهُ بِحَقِّ فَاطِمَةَ وَاَبِيْهَا
وَبَعْلِهَا وَبَنِيْهَا
وَالسِّرِّ الْمُسْتَوْدَعِ فِيْهَا
بِعَدَدِ مَا اَحَاطَ بِهِ عِلْمُكَ
Then repeat 10 times:
يَا اللَّهُ (x10)
Then say:
بِحَقِّ مُحَمَّدٍ وَ آلِ مُحَمَّدٍ
صَلِّ عَلى مُحَمَّدٍ وَ آلِ مُحَمَّدٍ
وَ عَجِّلْ فَرَجَ آلِ مُحَمَّدٍ
وَ فَرَجَنَا بِهِمْ يَاكَرِيْمُ
Then repeat 10 times:
يَاكَرِيْمُ (x10)
Then say:
بِحَقِّ سَيِّدَ الْشُهَدَاء
وَ بِحَقِّ جَمِيع شُهَدَاء كَرْبَلَاء
وَ بِحَقِّ جَمِيع اُسْرَى كَرْبَلَاء
وَ بِحَقِّ جَمِيع مَظْلُومِ كَرْبَلَاء
يَا اللّٰهُ
Then say:
وَ بِحَقِّ اَسْمآءُك الْحُسْنى كُلُّها
يَا اللّٰهُ
Then say:
وَ بِحَقِّ كُلِّ مَا هُوَ قَرِيْبٌ مِنْكَ
وَعَزِيْزَةٌ عَلَيْكَ
وَمَحْبُوبٌ مِنْكَ
يَا اللّٰهُ
Now ask for the most important need that you want to be fulfilled
This part is from the Ghufayla prayer after mentioning your needs to encompass everything else you wish for but were not able to include:
اللَّهُمَّ اَنْتَ وَلِيُّ نِعْمَتِي
وَ الْقَادِرُ عَلَى طَلِبَتِي
تَعْلَمُ حَاجَتِي
فَاَسْاَلُكَ بِحَقِّ مُحَمَّدٍ وَ آلِهِ
عَلَيْهِ وَ عَلَيْهِمُ السَّلامُ
لَمَّا قَضَيْتَهَا لِي
Have absolute faith that Allah will answer your prayers:
اَللّٰهُمَّ اِنِّيْۤ اَدْعُوْكَ كَمَاۤ اَمَرْتَ
فَاسْتَجِبْ لِيْ كَمَا وَعَدْتَ
اِنَّكَ لَا تُخْلِفُ الْمِيْعَادَ