Here's what I learned:
It's not the setting, the detail, or the research that makes your story historical but the way that the characters think. They should never think like modern people. If you want a modern viewpoint on history then stick your lead character in a time machine and send them on back. After all, it's modern people who would be horrified by the old way of doing things e.g. medical care, food consumed, socially accepted prejudice, etc.
Stop believing that people think the way you think. That's where research comes in. Read something written at that time (so you're stuffed if you're writing something set in a pre-literate society).
Conflict resolution in historical fiction may not ring true in a modern setting. Be careful to resolve it within the thought processes of the time.
You don't have to demonstrate your research by including every detail you've read about. It takes the reader from reading the book to watching the book.
Good betas are worth their weight in gold.
Address the history by the quality of the characters. If you took out the narrative description you should still be able to tell it's historical from the characters themselves.
The past can really surprise you - did you know that there were floodlit rugby pitches in 1880?