This writing is taken from the website ISLAM-QA.
Praise be to Allaah.
Firstly:
You have done well to ask this question, because you have asked how to prepare for the month of Ramadaan. Many people misunderstand the true nature of fasting, and they make it an occasion for eating and drinking, making special sweets and staying up late at night and watching shows on satellite TV. They make preparations for that long before Ramadaan, lest they miss out on some food or prices go up. They prepare by buying food, preparing drinks and looking at the satellite TV guide so they can choose which shows to follow and which to ignore. They are truly unaware of the real nature of fasting in Ramadaan; they take worship and piety out of the month and make it just for their bellies and their eyes.
Secondly:
Others are aware of the real nature of fasting in the month of Ramadaan, so they start to prepare from Sha'baan, and some of them even start before that. Among the best ways of preparing for the month of Ramadaan are:
1 –Sincere repentance
This is obligatory at all times, but because of the approach of a great and blessed month, it is even more important to hasten to repent from sins between you and your Lord, and between you and other people by giving them their rights, so that when the blessed month begins you may busy yourself with acts of worship with a clean heart and peace of mind. Allaah says (interpretation of the meaning):
"And all of you beg Allaah to forgive you all, O believers, that you may be successful"
[al-Noor 24:31]