There are certain things that one should keep in mind concerning the Dua:
1. Allah love it when we make dua.
The Prophet once said, “Dua is Ibadah” (Tirmidhi, Ibn Majah, and Abu Dawud). Since it is a type of worship, it is something that we must always do. This is even to the extent that the Prophet (Peace be upon him) said, “Allah is extremely displeased with the person who doesn’t do duaa to Allah” (Tirmidhi).
2. We must never stop making dua.
Dua must not only be a tool for coming out of hardship. It must not be conditional. One must always make sure that he makes dua to Allah. A person can never say that he needs nothing and hence he won't make a dua. We are always in need of mercy and blessing of Allah.
Prophet (Peace be upon him) said Whosoever desires that Allah answers his Duas in unfavorable and difficult conditions, he should make plentiful dua in days of ease and comfort.”
3. Make Dua for others.
When you make dua for others, the same dua is accepted more quickly. It may happen that someone makes dua for you too and it gets accepted too.
There are certain ayahs in the Quran such as the last Ayah in Surah Nuh, the meaning of which is, “O my Lord! Forgive me, my parents, all who enter my house in Faith, and (all) believing men and believing women: and to the wrong-doers grant Thou no increase but in perdition!”
If you are to recite this verse, then you get a sin erased for every Muslim living in this world. Also, the Prophet (peace be upon him) said, ”Duaa for a person not present is accepted quickly by Allah”.
4. Trust Allah.
Have complete faith that Allah will accept and answer your prayer. Having no belief in the power of Allah will not get your dua answered.
The Prophet (peace be upon him) said, “When anyone of you do Dua then don’t say “Oh Allah! Forgive me if you want“, “Have mercy on me if you want“, “Give me subsistence if you wish” rather believe completely that HE will do whatever HE wishes. Nobody can force Him.” (Bukhari)
5. Make dua in Sujood.
The best time to make dua is when one makes dua in sujood and at times between Adhan and Iqamah.
Prophet (Peace be upon him) said, “Three types of people’s Duas are not rejected:
1) At the time of Iftar the person who has fasted.
2) Adil ruler’s Dua.
3) The Dua of the oppressed. Allah raises the Dua of the oppressed on the clouds and the doors of heaven are opened for it and Allah says, “Oath of MY Majesty and Honor! I will help and aid you. Even though if the help is after few days.” (Tirmidhi)
Another Hadith listed another three in which the Prophet (peace be upon him) said, Three Duas are such in which there is no doubt of their acceptance:
1) Father’s Dua
2) Traveler’s Dua
3) Dua of the oppressed”. (Tirmidhi, Ibn Majah)
May Allah subhana wa taala accept all our Duas and bless us with his mercy.