below is an excerpt about preparing for Ramadan from Shaykh Salih al-Munajjad. The full text can be found here:
How can we prepare for Ramadan?
We can prepare for Ramadan by taking stock of ourselves and recognizing our shortcomings in living up to the Two Shahadahs (Testimonies of Faith, i.e., there is no god but Allah and Muhammad is the Messenger of Allah), or our shortcomings in fulfilling our duties, or in not keeping away from the desires and doubts that we may have fallen into.
We should set ourselves straight so that in Ramadan we will have a higher degree of faith. For faith increases and decreases. It increases through obedience to Allah and it decreases through disobedience and sin. The first act of obedience that a person should achieve is that of being a true slave of Allah and believing that there is none that is rightfully worshiped except Allah, so he directs all kinds of worship to Allah and does not associate anyone else in worship with Him. Each of us should realize that whatever has befallen him could not have missed him, and whatever missed him could not have befallen him, and that everything happens by the will and decree of Allah.
We should avoid everything that could undermine our commitment to the Two Shahadahs. This means keeping away from bid`ah (innovations) and things that have been introduced into the religion. We should also follow the principle of al-wala’ wal-bara’ (loyalty and friendship vs. disavowal and enmity), by taking the believers as our friends and by regarding the unbelievers and hypocrites as enemies, and we should rejoice when the Muslims gain a victory over their enemies. We should follow the example of the Prophet (peace and blessings be upon him) and his Companions and adhere to the Sunnah of the Prophet (peace and blessings be upon him) and the way of the Rightly-Guided Caliphs who came after him. We should love the Sunnah and love those who adhere to it and defend it, in whatever country they are and whatever color or nationality they are.
After that, we should take stock of ourselves and recognize our shortcomings in doing acts of worship such as praying in congregation; remembering Allah (dhikr); paying attention to the rights of neighbors, relatives, and the Muslims; spreading the greeting of salam; enjoining good and forbidding evil; urging one another to follow the truth and be patient and steadfast in doing so; being patient in avoiding evil actions and in doing good deeds; and accepting the decree of Allah with patience.
Then we should take stock of ourselves, our sins, and our following whims and desires. We should stop ourselves from persisting in that, whether the sin is great or small, whether it is a sin of the eye, by looking at that which Allah has forbidden; or by walking to things that Allah does not approve of; or by using one’s hands to strike in a manner that Allah is not pleased with; or by consuming things that Allah has forbidden such as riba (interest) and bribes, or any other means of consuming people’s wealth unlawfully.
We should never forget that Allah stretches forth His hand during the day to accept the repentance of those who sinned at night, and He stretches forth His hand at night to accept the repentance of those who sinned during the day. Almighty Allah says:
(And vie one with another for forgiveness from your Lord, and for a Paradise as wide as are the heavens and the earth, prepared for those who ward off (evil); those who spend (of that which Allah hath given them) in ease and in adversity, those who control their wrath and are forgiving toward mankind; Allah loveth the good; and those who, when they do an evil thing or wrong themselves, remember Allah and implore forgiveness for their sins — Who forgiveth sins save Allah only? — and will not knowingly repeat (the wrong) they did. The reward of such will be forgiveness from their Lord, and Gardens underneath which rivers flow, wherein they will abide for ever, a bountiful reward for workers!) (Aal `Imran 3: 133-136)
(Say: My slaves who have been prodigal to their own hurt! Despair not of the mercy of Allah, Who forgiveth all sins. Lo! He is the Forgiving, the Merciful.) (Az-Zumar 39: 53)
(Yet whoso doeth evil or wrongeth his own soul, then seeketh pardon of Allah, will find Allah Forgiving, Merciful.) (An-Nisa’ 4: 110)
By taking stock, repenting and seeking forgiveness—this is how we should welcome Ramadan. The Prophet (peace and blessings be upon him) said, “The smart man is the one who takes stock of himself and strives to do that which will benefit him after death, and the helpless one is the one who follows his own whims and desires and engages in wishful thinking, (assuming that Allah will forgive him regardless of what he does and that he does not need to strive to good deeds).” (Reported by Al-Bukhari)
The month of Ramadan is the month of great gains and profits. The smart trader is the one who makes the most of special occasions to increase his profits. So make the most of this month by doing lots of acts of worship, praying a great deal, reading the Qur’an, forgiving people, being kind to others, and giving charity to the poor.
In the month of Ramadan the gates of Paradise are opened and the gates of Hell are shut. The devils are put in chains and a caller cries out each night, “O seeker of good, proceed! O seeker of evil, desist!”
So, O slaves of Allah, be among the people of good, following the path of your righteous forebears who were guided by the Sunnah of your Prophet (peace and blessings be upon him), so that we may end Ramadan with our sins forgiven and our righteous deeds accepted.