"Account yourselves before you are taken to account!"

"Account yourselves before you are taken to account!" `Umar ibn al-Khattaab [Az-Zuhd of Ibn-ul-Mubaarak]
"On that day every person will be confronted with all the good he has done, and all the evil he has done, he will wish that there were a great distance between him and his evil deeds. And Allah warns you against Himself (His Punishment) and Allaah is full of Kindnessto the (His) slaves." [Soorat Aale-'Imraan 3:30 ]
Ibn Katheer explain the aforementioned aayah: "On the Day of Judgment all his good and evil deeds will confront him, as Allaah, the Most High, says, 'On that Day man will be informed of what he sent forward (of his evil or good deeds), and what he left behind (of his good or evil traditions).' " [Tafseer Ibn Katheer 1/338]
One may feel that after doing an action he will never see it again. Especially, if it is an internal or hidden deed, like ar-riyaa, jealousy, hatred for the believers, desiring the evil, etc.
"Knows he not that when the contents of the graves are brought out and poured forth. And that which is in the breast shall be made known." [Soorat Al-'Adiyaat 100:9,10]
"That which was hidden in themselves will be made apparent" [Tafseer Ibn Katheer 4/545] such that, "whosoever does good equal to the weight of an atom, shall see it. And whosoever does evil equal to the weight of an atom, shall see it." [Soorat Az-Zalzalah 99:7,8]
A person's day is filled with actions. Actions are done and forgotten about. Forget them we may, but it is them we will have to answer about on that Day. Allaah says, "That He may ask the truthful about their truth." [Soorat Al-Ahzaab 33:8] If Allaah, the Most High, will question and account the truthful then how can the rest of mankind be exempt?
Righteous actions are extremely valuable, for whosoever's good deeds are more than his evil deeds and tips the scale by an atom's weight will enter into Jannah by Allaah's Mercy.
Therefore, a believer must focus on his actions, and focusing of ones actions entails the following:

Preparation:
The slave of Allaah needs to prepare and make his soul ready for the day ahead. After Salaatul-Fajar he should make himself realize that the day has many hours. He should hope to fill every hour with that which will benefit his soul. He should hope to fill every hour with that which will benefit his soul. He should try to grasp on to the treasures of righteousness that the day holds for him.
He should hope to keep every hour free from that which will harm his soul. He should try to avoid the evil that the day has in store for him.
So, he should advise his soul to be a soul that strives to obey Allaah, keeps away from laziness, does not waste time, and takes a maximum benefit of the day. After advising his soul he should focus on:

Self-Examination:
The examination of the soul occurs at three instances: before the action, during the action, and after the action.

Before the Action:
The slave of Allaah must check his intentions before the action; is it only for Allaah or is it for something or someone else ? If it is for other than Allaah then he must know that it is something evil. It then necessitates that he busy himself in purifying his intention and making it only for Allaah, Al-Wahid.
He must also make sure that the act of worship will be done in the manner performed by the messenger of Allaah as understood and implemented by the Sahaaba (his companions).

During the Action:
The slave of Allaah must be aware of Shaytaan and his whispering during the action. He must check to make sure that his intentions are continuously wholly for Allaah. He must strive to perfect his actions as much as possible.

After the Action:
"O you who believer! Fear Allaah and keep you duty to Him. And let every person look to what he has sent forth for the tomorrow, And fear Allaah. Verily, Allaah is All-Aware of what you do." [Soorat Al-Hashr 59:18]
"And let every person look to what he has sent forth for the tomorrow", Ibn Katheer said it means, "You take yourselves into account before you are taken into account." [Tafseer Ibn Katheer 4/342] Therefore, we are to "see what we have sent forth from the deeds for the Day of Judgment." [Nafhatul-`Abeer min Zubadatut-Tafseer p.1349]
As after Salaatul-Fajar the slaver of Allaah prepares himself for the day, then similarly the slave must take himself into account at the end of the day. Like a business man who accounts at the end of the day and checks whether it was profitable day or not. The slave of Allaah must question his soul and ask. Did I fulfill my obligations? Did I make sure I had Ikhlaas (sincere and pure intentions only for Allaah) in all my actions or did I do actions for the show of people? Did I benefit from this day or not? And if he evaluates that he is in loss, then he should undergo:

Discipline:
After taking oneself into account and realizing that one is in loss, one should discipline oneself by doing good deeds hoping that the good deeds will wipe out the evil deeds.
This was the practice of the Sahaaba, as is narrated about `Umar ibn Al-Khattab that he left his orchard to pray Salaatul-'Asr. Upon reaching there, he found that the people had already prayed, thus missing the Jama'ah. As a result, he returned to his orchard and gave it away as charity to the needy. [Mukhtasir Minhaaj-Al-Qaasideen p.379]
The ones who will benefit are those who take themselves into account before they are taken into account. For being taken into account in the Hereafter is not a light matter, the Messenger of Allaah said "Anybody whose account is questioned will be punished." [Saheeh Al-Bukharee 8/#543]
So let every soul take itself into account and exert itself to improve its deficiencies and shortcomings for the matter is as `Alee ibn Abi Taalib said, " for today there is action but no accounts, and tomorrow there will be accounts, but no deeds to be done." [Saheeh Al-Bukharee 8/chapter4]
Hasan Al-Basaree (a student of Ibn Mas'ood) said, "O Son of Adam! Surely, you will not acquire the reality of Imaan until you do not pick out the defects in people of which you have in yourself, and until you start to cure that defect from yourself, so you correct it. So when you have done that, you will not have corrected a defect except that you will find another defect that you did not correct. When you do that you will be specifically busy with yourself. And the most loved of the slaves of Allaah is the one who is like that." [Sifatus-Safwah 3/234].
Ahmad bin Hanbal reported that Allah's Messenger (sallalahu walayhe wasalam) said, "If a slave remains in prostration from the day he is born till his death and remains obedient to Allah, still he will consider his worship insignificant on the Day of Judgement and will long to return to the world to do more righteous deeds." [Tafseer Ibn Kathir]