There are always times when you zip, gzip and bzip2 files and directories to try and gain the highest compression ratio you can. But, have you tried LZMA compression? LZMA compression routinely obtains the highest compression ratio for any file type or directory of files. If you haven’t tried it, give it a try in Terminal.
For a file:
tar cf file_compressed.txt.lzma --lzma file_to_compress.txt
For a directory:
tar cf directory_compressed.lzma --lzma ~/Directory
LZMA compression will impress!
If you have another method of compression that you find generally gives you a better compression ratio for a varied type of file types, please leave a comment below.