How would a person start translating classical stories from the Han dynasty?
imo, the story is straightforward, and easy to compenhend.

here's my suggested interpretation:


  世間多有狗作變怪．朴殺之．以血塗門戶．然眾得咎殃


there're many canine monsters in the world (世間多有狗作變怪)

kill a dog (朴殺之), use it's blood to paint the door (以血塗門戶); but, people would have bad luck and disaster (然眾得咎殃).


  謹按．桂陽太守汝南李叔堅．少時為從事


here's a legend (謹按): the administrator (太守) of 桂陽, mr 李叔堅, whose was born in 汝南, was a 從事 (an official position) when he was young.

[name and official title were not translated]

edited.

well, a more precise translation of "謹按" is "cautious note" (謹慎+按語). however, mr 應劭 used this term so often, that; these're always part of the text, not as explanatory note of particular sentences/paragraphs.

my apologies for any confusing caused :(


  在家．狗人立行．家言當殺之．叔堅云．犬馬諭君子．狗見人行．效之何傷


[one day] when he's at home (在家), his dog stand, and walk like a man 狗人立行. his family members said they should kill it (家言當殺之).

he said (叔堅云): "dogs and horses are metaphors of superior person (犬馬諭君子). so, our dog observe human's behaviour (狗見人行), and make replication, what's the problem? (效之何傷)"


  Any tips for translating these types of stories in the future


one need certain level of competence to read classical / literary chinese; prior to make translation. the only method is read more, and more.

have fun :)