Like most European languages, English has been subject to many influences. Just because a particular turn of phrase is a little unusual doesn't mean it comes from Old English; it could be from Norse, Latin, Norman French or even any of the Celtic languages (for example, the rare construction "he has a big thirst on him" comes from the language that became modern Welsh). An unusual construction could also be an artificial construction, contrived by a certain class of author, perhaps attempting to follow some pattern in classical Greek or Latin.
I can't give you any tips on literature, but apparently, studying the West Friesian dialects spoken in some of the islands off the coast of the Netherlands is a good way to get an insight into Old English -- it's closer to Old English than modern English is.
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