When I do start getting ideas for works related to what I am currently working on, or even something I have completed, the ideas often come too fast for me to implement them as I get them. After all, hand needlework is not a fast medium. This is where my sketchbook comes in handy.
I am not a fast drawer. I can draw realistically but it takes me FOREVER!!!!!!!! So my sketchbooks are not art in their own right, as many artists' are. They are records of ideas, enough information for me to remember, in 5 months or 2 years, what the idea was. They are as much words as they are sketches. I record the idea, the date, sketch whatever bits and pieces I need to make the idea clear. I write colors or effects I want to achieve. I always record whatever the inspiration was. If possible I glue a picture of the inspiration into the book. Some of the ideas are worked out in fair detail complete with color (I usually use colored pencil, maybe a bit of watercolor pencil). But most of the ideas are in plain pencil with lots of notes.
I often go back through these sketchbooks, looking at old ideas, adding thoughts to them, filling in the sketches a bit more. And, when I have time and if the idea still strikes me as a good one, I will take an idea from a sketchbook and create it in thread.
By using sketchbooks in this way I don't lose that idea for another step in the series. And I am not as pressured to create it immediately. I have time to look over the idea, think it through, decide if it really is another step I want to take in the series.