This is obviously difficult question to answer as it's so broad, getting into issues of historiography and popularVsacademic writing. It's also likely to be different from one subject to another. In my areas of study I can normally tell quickly what books are going to be like by the way they are marketed, who writes them, and what they physically look like. (naval history has a lot of shiny coffee table warship picture books and a lot of nationalistic war porn. Even before you get to the sub-par semi academic books)

But ignoring specific debates regarding academicVspopular I think you need to ask yourself why you are reading it? How much narrative do you need for enjoyment? How many footnotes can you cope with? Assuming you want a nice informative read but without having to constantly flip between footnotes and bibliography etc I would suggest the following simple ideas.

1. Find one of the most academic texts you have come across in your subject so far and look at the bibliography. Find some books that fit your interests, especially the more 'general' works. Take note of any of the more frequent authors.

2. Google them. I know this seems a glib suggestion but you can find out very quickly a lot about that author and that work. While I certainly wouldn't rule out non historians in general, it can give you an easy way of filtering out the obvious guff.

3As a rough rule of thumb I would suggest that if you can find a book on Amazon or other major seller easily for a reasonable price they are likely accessible for the non academic but informed and interested reader. Most of the academic books will be either too expensive, out of print, or you won't find them easily.

3. Those authors you found in the bibliography, Google them. Find those you think are the most widely published authors or those who seem well established.

4. Use Google scholar. Type in a author or a title and you can quickly see if other works reference them.

5. From this list of authors see if you can find them on a popular book seller. Chances are that the most well respected historians will all have had a crack at good mass audience book at some point. Try that one. You will then hopefully have a good academic pedigree purposefully writing to a non academic audience. They should hopefully still be on their best behaviour as they still don't want their peers judging their academic work by the failures of an ill-researched popular work.

This is not a fool proof plan. You still run the risk of either getting a book to dry for you or too lightweight (or flat wrong). You are also more likely to get a mix of older successful works where the academic historiography has moved on from, but are well known enough to get popular readers. Or the most recent releases.

6. Alternatively to all that try just searching for something more specific. This might find you a more niche book that is likely to be better reaseached. If you can still find it on amazon it is probably still an accessible read.

As an example years before I started studying postgraduate I got fed up with what felt like gaping holes in the general popular work. And fed up of things that just felt like poor understanding of wider contexts by authors. So in the case of Naval History I got really fed up with the history of the interwar period. Popular stuff is full of lamentations of scrapping ships and limiting seapower, naive politicians and handwringing pacifists emasculating the navy etc etc. Economic context is extremely poor.

More specific searches just in things like amazon ultimately led me to work that was far more academic but still readable. These works stand alone for the casual reader but can also lead you further to other work. 4 books I read as a casual informed reader for fun I later found are significant works in the historiography of the subject and still referenced by historians.

As for assessing accuracy, don't be frightened of footnotes. They are the best place to give you a clue where the author got their information. Another book? Which ones? Academic sounding ones? Or ones that sound pop? Do they use journal sources? Journals are an excellent clue they actually have read some recent history on the subject. Footnotes are also the best places to pick up new books to read via the process previously outlined.

It's also where you, even as a casual reader, can start to question some of their ideas. If it uses primary sources, which ones and how?Has it only been sourced from 1 type or country etc. You can tell a lot about what type or style of history you are reading by the archive types they use. Memoirs? Personal papers? Court records? Government papers? Its sometimes enough to give you a clearer picture of what you are reading and where has it come from.

Another thing to look for is what basic assumptions or context your author takes for granted with no evidence whatsoever, just common 'well known' narrative. This is especially common with context outside the subject matter such as background politics, social issues, and economics. This is the baggage that often affects their ideas in negative ways.

Have fun. Footnote-literature rabbit holes are the best(/worst)

Edit. I have no idea what happened to my formatting and numbers on mobile