On Windows there is a nice little tool called latexdaemon that can handle "precompiling the preamble" (and thus speeding up compilation) automatically. It doesn't require any additional setup: one can simply run
latexdaemon --ini=pdflatex mytexfile.tex, and from there on it'll recompile the tex file each time it changes with the custom format file optimization (which I don't completely understand). It also provides a console where one can force recompilation manually, or force full recompilation (without the custom format file).
I am looking for similar tools that run on OS X.
On this site I have found several questions about precompiling the preamble, but none of them automate the process: they all require splitting the preamble into a separate file manually. I am looking for a tool that will spare me this trouble, and will let me start working on a new tex file with a single command, without the necessity to manually create multiple files and set up things each time.
Update: I tried to figure out how latexdaemon works, and the relevant bit for generating the format file is here. Looking at that code makes it clear that it's way above my level of (very basic) LaTeX knowledge though.
I think the main question which I haven't been able to solve on my own was how to generate and use a format file without splitting off the preamble into a separate file.