No it's neither random nor wholly personal in either language. There is, too some degree, method to the madness though obviously within the most common sentence patterns there's going to be variety since they're both inflextional languages.
That's the short answer, the long answer would entail reproducing several pages from either a good grammar or composition book. That's actually your best bet to begin with. Then cross reference them vs literature. Admittedly we can see that literary word order varies from what we can ascertain of common speech, but still, you can pick up on these tendencies. Greek tragedy, for example, often appears nearly random. Frustrating, but then scholars like Dik have shown this is not the case either.
Panhuis' Latin Grammar has an excellent section on Latin word order if you can get it, a good 6/7 pages and based on modern, communicative, linguistics so easy to follow.
Will not answer questions which only need a basic knowledge of grammar. Pay attention to the textbook.