D'Ooge gives some explicit notes on word order; I've collected those in my notes:
In a latin sentence the most emphatic place is the first; next in importance is the last; the weakest point is the middle. Generally, the subject is the most important word, and is placed first; usually the verb is the next in importance, and is placed last. The other words of the sentence stand between these two in the order of their importance. Hence the normal order of words – that is, where no unusual emphasis is expressed – is as follows:
subject – modifiers of the subject – indirect object – direct object – adverb – verb
Changes from the normal order are frequent and are due to the desire for throwing emphasis upon some word or phrase.
Possesive pronouns and modifying genetives normally stand after their nouns. When placed before their nouns they are emphatic.
An adjective placed before its noun is more emphatic than when it follows. When great emphasis is desired, the adjective is separated from its noun by other words.
The pronominal adjectives (unus nauta) regularly stand before their nouns.
When a noun is modified by both a genitive and an adjective, a favourite order of words is adjective – genitive – noun.
A modifying genitive or adjective often stands between a preposition and its object.*
Interrogative words usually stand first.
The copula (esse) is of so little importance that it frequently does not stand last, but may be placed wherever it souns well.
*This one contradicts the adjective-preposition-noun word order; however, in the same exercise where he gives this as a note (i.e.118), he also uses 'multis cum lacrimis'.
I've read somewhere that Latin writers sometimes use words as brackets, i.e. putting words that obviously belong together round other words of the same phrase.
Anyway, the exact word order in the key is not that important; make sure that you've got the grammar right, and play around with the word order. I often reread the dialogues and longer pieces, looking especially at the phrases and order.
Hope this helps.