I’m pretty sure there is no rough and ready way to deduce the correct I7 syntax or the keywords of the language (though there are a few rules of the kind, like definite and indefinite articles never makes a difference (except in a few set phrases)).
Inform 7 for Programmers and the I7 Cheat Sheet (as well as the Rules Chart) provide good overviews of the language and the way Inform works. You’ll find links to them here: [url]Inform 7 documentation and resources].
I’m also fond of the extensively commented official pdf version of the I7 Standard Rules, called Appendix A, that can be found here: http://inform7.com/sources/src/stdrules/Woven/index.html.