I experience this all the time. I cannot be sure if it is a product of bipolar disorder or not. It still remains to be seen if I am bipolar. I can say with certainty that the degree to which this occurred greatly increased right before I became manic. It was like my natural tendency was amplified to an extreme degree.

My mind is always multitasking and shifting modes. At any given point I am thinking about and/or working on 5, 6 sometimes more things. Typically, I am physically doing something while thinking through or planning several other things. It is usually a very disjointed experience, but it adds up over time to create complete initiatives. I recognize this lacks in efficiency and quality of experience. I've actually been working to implement something better for myself recently, so your question comes at a great time.

Some of this is a product of my environment. My little ones interrupt my train of thought often and starting and stopping tasks is just a reality of being a mother. However, there are times when I could completely connect with the moment and I do not simply out of habit.

First, I recognized that there are times when this method of thinking is beneficial for me or brings me greater value in the moment. For example, when I am folding laundry or doing the dishes I am completely fine with letting my mind wander. It helps me cope with the repetitive and mundane nature of those tasks. However, I find the experience is even more valuable if I can decide upon a particular train of thought and stick with it. So for example, I might decide to use my laundry time to also offer gratitude for my blessings and pray for those in need. Otherwise, my mind is all over the place. Recognizing I might wander and instead focusing to a limited scope helps me create more value in the moment.

It also helps when I spend some time in the morning planning out my day. I lay out the tasks which include the things I need to physically do as well as the things I need to think through. I also take time to consider anything that might keep me from meeting my goals and brainstorming strategies to help me get around those issues. I use all of this as the inputs needed to create a loose plan for my day.

As I go along, I find that my mind wanders less if I know I've already done the work to plan for everything and allocate time accordingly. It's like know I can just cruise along and follow as opposed to figuring it all out as I go. If in get into my day and things get crazy, I step back and realign with my plan. I adjust as needed if something comes up that genuinely requires my attention. I put other things that can wait in the 'parking lot' and plan for them later when they become a higher priority.

That's a condensed version of how I'm trying to go about it. It leverages the core strategies of how my teams used to manage work and respond to change in a professional setting. I still multitask, but it is planned for and much more streamlined. It accounts for lag between tasks and isn't just my mind doing 10 things at once because it can. So in your case, doing something like banging out an outline for the next chapter in your book while your cookies bake makes sense. Doing that with the tv on and thinking about what's for dinner and also what to get your Dad for Christmas and also how to secure that agent you're wanting to work with does not.