What is the easiest option to start making instructions?
After testing several software (and figuring out quite a few are not compatible with each other), I tested Leocad, and was able to easily create models and generate instructions.

In Leocad 0.82, going through "Print Preview…" and then printing to PDF generates simple and clean instructions.

http://raphink.github.io/lego_models shows the results I got with that method.