If you program display a lot of repetitive strings on LCD with slight different wordings at different part of the program, you can assign the common part of the string to a string variable, and then combine the string variable with the specific text that are different at different part of the program to display a combined longer string. This way you can save quite a lot of memory.
If your PLC is with firmware r47 and above, you can also purchase an M2018P extended EEPROM module for $20. This increases the program EEPROM memory to 8190 words and data EEPROM to 7700 words.
The firmware revision can be found by the "Controller->Get PLC Hardware Info" command on the TRiLOGI software. For firmware revision r49, it will show up as "T100MD+r49".