There are two main techniques for remember quotations and lines:
Professional actors are said to learn lines most effectively by rereading a play or parts in a play many times over a short period. As an example, they may read something to be remembered 5 to 10 times a day over 4 days.
2. Keyword/Journey System
An alternative approach using mnemonics is to use the journey system, with a stop for each line.
At each stop you can either code the key images or words, or can adopt a technique where you associate each word in the line.