You can memorize 1 scripture or work to memorizing all three for each month.
To help you memorize scripture be sure to journal, study, and pray through each scripture. Allow your self time to meditate on these scriptures for multiple days.
A good way to think about this, to take the tea bag approach. Allow the scripture to sit with you to allow for it to saturate.
When you considerer meditating:
1. Picture It
2. Ponder It
3. Personalize it
4. Pray Over It