One really easy one: write a shell script to do most of the image building (run by the Dockerfile), instead of adding a bunch of RUN directives in the Dockerfil

One really easy one: write a shell script to do most of the image building (run by the Dockerfile), instead of adding a bunch of RUN directives in the Dockerfile, especially if you clean up intermediate files with a "make clean" or something. Each directive in the Dockerfile adds a layer, which adds container setup overhead, and also "locks in" all filesystem space usage at that point.