Once you start to work and make progress on your project, it may look like all sunny blue skies ahead. But it is important to make plans for not only in case of writer's block, but also for what to do when that flowing creativity results in too many ideas. The newest idea threatens the one you are slogging through and looks like more fun/easier to execute/more interesting/what have you... If you have been at this for a while, you know following this path means you can land up with a bunch of good ideas and no completed projects.
The siren song of a new idea can spell death for the current project if it is abandoned before it comes to full bloom. That doesn't mean you have to hold off until this project is wrapped and launched before getting into the new idea. You just have to be smart about it. Here is the strategy to both stay the project's course and not lose the new ideas:
1. write it down
Taking the time to sketch it out means you won't lose the inspiration. You can add more ideas as they come up. Just keep the notebook or digital file nearby as more details are sure to come to you as you continue to work on the current project. If you don't get rattled by it, you can just enjoy it as a side benefit of creative juices flowing. And celebrate! You are generating twice the ideas you anticipated.
2. see if you can tie it into a series
Sometimes new ideas arise because you have hit upon a theme that especially resonates with you or the market is timely and references to it keep arising in daily life. Don't worry that you will lose out this opportunity. If it doesn't tie into your current work as a supporting book or series addition, just keep working on your notes. It might be a stand alone series by itself. And given the success model that sees authors of multiple books hit the best seller lists, this is a direction you'll want to develop in.
3. use it as a reward
Working on a new idea when it's hot has the side benefit of feeling like a reward. Working on your current project for a timed set (even 10 minutes) and then switching to develop your new idea for another five or ten is a model that when repeated can have you producing what you need to on your current project while not losing the momentum of the newly hatched ideas.
4. test it out
As you develop it, give your new idea some test runs by writing a short scene, posting an article or blog post on the topic, or discussing it with your fellow writers and beta readers. Taking it for a trial run lets you see if it is an idea worth pursuing and how much interest there is for it.
5. prioritize it
Not every new idea will make the cut and go long term project. That's ok. Keeping a running list with time frames and markets for them (agent submissions, short story contests, guest blog posts, linked in articles... etc) means you will spend the appropriate amount of time on each project according to its purpose. If you use vision boards, mapping out each project on one bulletin board (virtual or not) is a good way to keep an eye on each of them.
Let me know if this touches on your experience with new ideas. Do they help you or harm you when it comes to your production?