Yes, doodling is the answer. I practice on paper, dry erase board, Plexiglass, chalk board... whatever is available at the time. The key is to develop the skill to 'see' where you need to go next when you come out of a spiral.
I was recently trying to work out a cabled feather that I had in my head. (Two feathers intertwining like a cable.) I probably filled 20 sheets of paper trying to work it out before I was ready to try it on my plexiglass over the practice table runner. Once I'd done it on the plexiglass how I liked it, I transferred reference lines onto a scrap practice piece and finally did the practice runner. This week, I'll be transferring the reference lines onto the real queen sized quilt and finally get quilting.
Quilting, even FMQ takes a lot of planning and practice. Stick with it and it will become second nature.