enhance Tesseract 4 accuracy

[Ibr]

Hi,

I'm using tesseract 4.00alpha tesseract with leptonica 1.74.1 on Ubuntu 14, I use it to create LSTM files, when I want to make a detection for any image I use both trained data with the LSTM file, and the command is tesseract image.tif output -l ara --oem 1

the results is good except for one character, so my question is how to enhance the accuracy for a  specific character

thanks