Currently the malpartidia LiquidCrystal_IC2 library is the library of choice. You can get it here: FM New LiquidCrystal
Use the sketch found here i2cLCDguesser to determine the parameters to use with that library.
Use the tutorials found here LCD Displays (Blue and YELLOW) with I2C/TWI Interface to get started using the library.
Thanks! Unfortunately I already saw these, and they weren't much help. I tried adjusting the contrast, but that didn't work. I looked at a I2C ID Checker and determined that the 20x4 display has a ID of 0x27. I've updated the LiquidCrystal_I2C to 1.2.1, but that didn't help either. The IDE does not seem to be liking lcd.//any command. Would you possibly happen to know why?