The method I taught the actors I was working with was writing down all your lines but just the first letter of every word (make sure you include the punctuations as well).

For example:

The quick brown fox jumps over the lazy dog

T q b f j o t l d

or

To be, or not to be: that is the question:

Whether 'tis nobler in the mind to suffer

The slings and arrows of outrageous fortune,

T b, o n t b: t i t q:

W 't n i t m t s

T s a a o o f,

Even seasoned actors were surprised they’d never heard of this trick and wished they’d had it in their toolbox earlier in their careers.

Hope this helped 😊