I freely admit that my Cantonese and Mandarin are both extremely rusty (and never all that good to begin with, TBH), and probably someone else can explain it a lot better, but I'm getting the impression that you may be expecting a 1-to-2-word imperative the way that English does it (i.e. Leave! or Wake up!), while Chinese instead tends to do these multi-word imperative sentences (for conversational use, at least), which often end with word-particles (啦
lā in Cantonese, 吧
ba in Mandarin), usually include an object or adverb along with the imperative verb (or use what amounts to a conceptually compound verb to express a single action), and sometimes include a pronoun as well.
So for a Mandarin-ish feel, perhaps make your commands multi-word and consistently end them with the same particle.
(Also, I highly recommend Mark Rosenfelder's
The Language Construction Kit for useful tips on creating your invented language, and Wikipedia has a decent summary write-up on
Mandarin grammar which may be of help to you.
Of course, if you really want to give it a consistent accurate basis, one of the best real-world concise explanations of Mandarin, IMHO, is the Routledge Grammar series'
Chinese: An Essential Grammar volume by Yip Po-Ching & Don Rimmington (linkage to
Amazon, where you can browse the Look Inside previews), which you may be able to obtain via your local library.)
Hope this helps.