بسم الله الرحمان الرحيم
السلام عليكم ورحمة الله وبركاته
Firstly, may Allaah Ta`aalaa reward you for having memorised His
Kalaam and may He accept it from you, Aameen. The rewards and benefits of Hifz are innumerable, and it is a gift from Allaah Ta`aalaa; not all people have been granted this
Mubaarak Gift. Hence, it is of utmost importance to make
Shukr to Allaah Ta`aalaa for having chosen you to be a recipient of this gift, and for having made it easy for you to memorise the entire Qur'aan.
Thereafter, a Haafiz/Haafizah should aim to do at least one Juz/Paara (Portion, from the 30 portions) of the Qur'aan every day. In this manner, one
Khatm of
Muraaja`ah/Dor (Revision) will be completed every month, In Shaa Allaah.
Aim to do at least this much every day, In Shaa Allaah. It is also very important that you read Qur'aan in
Qiyaam-ul-Layl (Tahajjud Salaah), as well as the Sunnah and Nafl Salaah you perform throughout the day. This will strengthen your Hifz tremendously, In Shaa Allaah.
As for the Juz/Paara itself; you can split it up throughout the day. Perhaps do
Muraaja`ah/Dor of one quarter after each Salaah; or, do half a Juz after Fajr and half after Maghrib; or, set aside an hour or two to do the entire Juz in one sitting. Whatever you are most comfortable with. The important thing is to do that one Juz everyday.
Another thing to remember is that a very important aspect of
Muraaja`ah/Dor (Revision) is
Takraar (Repetition). You have a long-term and short-term memory. Reading a thing once or twice will only put it in your short-term memory. You may be able to recall it right now, but if you are asked about it a week down the line, you would have forgotten. That is where
Takraar comes in. If you had read that same thing 100 times, for example, then you would definitely In Shaa Allaah recall it a week down the line and even longer. Hence, if you are experiencing difficulty in a particular page/quarter/Juz, then simply do
Takraar (repetition) of it; read it over and over and over until it has become ingrained in your heart. Read it while walking around doing your daily business, like Dhikr, because the
Kalaamullaah itself is a great form of Dhikr.
The most important aspect is Du`aa; ask Allaah Ta`aalaa to preserve the Qur'aan in your heart. Make this Du`aa in Tahajjud and after all of the daily Fardh Salaah. Bi-Idhnillaah, the Qur'aan will never be taken away from you.
May Allaah Ta`aalaa make it easy for you,
آمين يا رب العالمين