It's probably a really small tip, but something that annoyed me a couple times. We use Quick Look (I think that is what Apple calls the feature) all the time to preview files, especially text or html files. So wouldn't it be sweet if we could do that on Markdown files, since we usually have a Readme.md file in most of our projects. OR, I like to create a `docs` folder in most of my projects as a place to store notes about the project in markdown format. So wouldn't it be sweet to simply hit spacebar and get a quick look at it? I think so. So let's add that!
If you are using Homebrew, this add on really couldn't be easier.
Check out the toland/qlmarkdown repository on Github.
You simply need to run `brew update` then run `brew cask install qlmarkdown`
Now just navigate Finder to the right directory, select the file you want to peek inside and hit spacebar. You should be able to Preview the contents.
If you want to remove this `brew cask uninstall qlmarkdown`