Personally, I have one NWT that took 3½ years to get it all read. The only way that I know I read it all is from checking every page and seeing what I had underlined in 4-color-pen. Besides that, I have 3 others that have large sections marked in them. All 4 of them have lots of my own marginal cross-references and language notes in them. One has all the Scripture references to the Bible Teach book in it. One is in the process of getting all the Scripture references to the Revelation Climax book in it.
My earlier KJV which I still keep has several pages of notes in the front and back covers relating to updating the English, using the 3-volume Merriam-Webster Dictionary that came with my Encyclopædia Britannica.
I also have dozens of versions of the Bible, mostly in English, but also in several other languages also. Some editions are only small portions, such as the Pentateuch, the Psalms, the "New Testament". I even have paraphrases, including a copy of The Cotton Patch Version of Paul's Epistles, by Clarence Jordan. So the bookstores where I live who sell Bibles and Bible-related literature have definitely made money off of me, (though I've never paid very much for any one item).
Sometimes I find a usage in the NWT puzzling. So I may use one/several other translations or reference books for understand the passage. (Some volumes in my collection have been bought with just one scripture in mind.) Then, I'll go back to the NWT and add marginal, clarifying notes. The meanings of cultural practices is important to me, especially in comparison to what I'm learning about what Jehovah loves and hates.
My hardcopy WT library is fairly complete from 1985 to present, and I have acquired most of the WT books back to 1950. My earliest WT publication is the Berean Bible Teachers' Manual from 1908.
As for non-WT reference material, I have already acquired several Bible Hebrew & Greek dictionaries, as well as Greek-English interlinears, Bible atlases, several English dictionaries/glossaries from various parts of the world. As well, I use the TNIV and the NWT online, as well Hebrew interlinears online.
Since I am treated as disfellowshipped, I do buy WT publications from local bookstores when I find them, regardless of what language they are in, so that when I find someone that I feel would appreciate reading them, I can put them to good use.
The difficulty with much of Bible reading is that the culture references of the average person today are often quite different from what the Bible writers used. I have found Jehovah's Witnesses to have the most nuanced, respectful, helpful understanding of these matters. The Insight volumes are useful to know about the value of weights and measures.
Marginal notes often starts from doing research on a day's-text/comments. For instance, I like to put the money into how many minutes/hours/days it took for a 12-hour agricultural laborer to make it. Then it seems more relevant. As well, I have one symbol for principles, another for key/pivotal Scriptures, etc.
I try to stay grounded by avoiding Christian Fiction novels such as by C.S. Lewis and J.R.R. Tolkien since their settings do not match either the world I live in nor the world of Bible times. I also avoid Christian Philosophy type books/shows that appeals to the emotions, but seem hard to apply to my own circumstances.
I find that I now spend about 1 hour each day reading the Bible and Bible-related works, and spending anywhere from a few minutes to several hours a day on JWD. Once in a while, when I go out or am on the phone, I can find myself in a Bible-related conversation, but not every day.
I do research where ideas come from, for greater understanding and respect of the playing field. I find that works that are too vague/general or get into ad hominem are counter-productive. I look for publications that try to teach interpersonal skills such as kindness and tough love and hope. Then I try to share what I've learned with others, such as what I'm doing here. I like it where we each can bring out the best in each other.