My suggested addition at the end:

- In order to make the code consistent, header files should be included in the following order, with each section separated by a newline:

block -> section (just because block is so heavily used in other contexts :P)

for -> from

Should we mention anything about internal 3rd party dependencies (ie: univalue) and external (ie: boost)? I've always imagined that internal dependencies should always come before external, though I admit I don't have strong reasoning for this beyond that it seems reasonable to me.