Ensure the source text is in a language that you do not understand.
If you are translating from a print edition, start by describing, in the target language, the physical appearance of the book.
1 Try not to “read” the text: avoid the temptation of interpreting any words that seem familiar.
If the book has any apparatus begin by describing its relative proportions.
1Cf. Packing My Library—the electronic text does not have its own physicality, it has a borrowed physicality which it shares with all other electronic books read on the same device.