I think that the phrase "study the bible" is a trademark of the Watchtower CORPORATION ... they have trademarked this BIG phrase to make people believe they are into something SO BIG AND SPECIAL when in fact they are not (we were not) ... now that I am a Christian I know that if you want to "study the bible", you either do it on your own as LouBelle said before and if you really really want to study the bible you go to a college where you can get even doctorates on bible studies and let me tell you this people know everything about it ... culture, languages (hebrew, greek, aramaic), peoples, geography, archeology, early christians by name, genealogy, awesome knowlege of the bible BUT even they have to personally "READ the bible" Medidate on in apart from their "study" of the bible ... I hope I am making sense ... (I am embarred now to think that I used to say that I was "studying the bible" what a joke !!!)
I am not into "studying" the bible, I read it and I do research subjects of interest. During my personal reading of the bible, I keep a notebook next to me where I write my thoughts about it, how can I apply it on my own life, sometimes I write prayers based on what I am reading, I make notes of God's qualities, thoughts, commands, likes, dislikes, I note how my feelings are same as God's. I also make notes of words that I want to research, towns, people, stories, for example right now I am going to research Job 14:14, I heard that in Hebrew Job question is: If a man dies will he live? Not will he live AGAIN? and how this question posed by Job through the ages is answered by Jesus ... do I think I have to make a big effort to do this research, NO, I wait for God to lead me to the right sources and then the answer will be in my heart, in my Spirit.
I don't know if you consider yourself someone that has a personal relationship with our Heavenly Father through Jesus, because if you believe then you will know that we have a helper that helps us to understand the living message of the bible when we read it.
You can read the bible along with a group or a partner, but everybody is different, your life (heart mind soul) has been shaped by what you have personally experienced, seen, read, heard, studied, been told by parents, friends, siblings, environment, geography, race, color, hundreds of factors, for the message of the bible to be a double sword: (Hebrews 4:12 For the word of God is alive and active. Sharper than any double-edged sword, it penetrates even to dividing soul and spirit, joints and marrow; it judges the thoughts and attitudes of the heart.) you have to personally read it and medidate on it and BELIEVE, trust what your spirit is telling you, that still small voice that yet JOLTS inside you. Believe in personal revelation because that's one of the things the HOly Spirit through the bible does for you. It is a double sword. JWs believe that the bible the book itself is the "double sword" and will quote anything from it to make you comform BUT as a Christian I now know that it is the Holy Spirit that will make that message of the bible match (so to say) your own Spirit (so billions of people will be affected different by that message - this has nothing to do with doctrines but renewal of the heart and mind).
I enjoy reading the bible now, with prayers it is the first place I go when I have problems and there is always an answer or promise ... I love to go through my notes and prayers ... I cry reading my own notes, everything in them have come to pass ... God has been so faithful... I didn't know what it was before but now I know that the bible has a living message for each of us individually, with the right heart and attitude, humility, repentance and total surrender to Almighty God through Jesus as Lord and Saviour, the Holy Spirit makes it comes alive for each one of us that seeks ...I know some peole don't believe but I believe and have faith.
Gosh, this became a long note, so going back to your question ... LOL!!!... the most productive way for me is: solitary (I like to go straight to the Holy of Holies)