Learn the defaults.

Many tools allow a lot of customizations, especially text editors. The thing is, if this level of customization is available, it is usually because the tool has a lot of functions/capabilities. A sane tool would propose bindings to these functions for easy/quick access by default. As all functions are accessible by default, it means you can use the full potential of the tool without tweaking it, so if you learn these defaults you can reach a high level of usability, and so, on each machine you would have access too, extremely quickly.
Learning defaults will also make you dig into your tools, and certainly learn a handful of neat little tricks!

The simpler, the better.

The unix philosophy strives for simple tools that are powerful for one specific task, and integrate well with other tools. When tools are simple, you can quickly learn them and get efficient again.
Simple tools are quicker to learn, easier to integrate and usually more robust (as they focus on a single task).
One great example is `dmenu` which can be used for basically ANYTHING requiring user input. Yet, it is simple enough to have it replaced by a similar application, like "thinglaunch": read list from stdin, outputs selection from stdout. That's only an interactive grep(1) command when you think about it, a great filter.