Keep it cheap.
Use all of your resources to find out as much as you can about your interest or idea. Search the internet, go to the library, see what's at the bookstore, look at magazines. Gather as much information you can. You may find out really quickly that it doesn't sound so good after all, or that the timing just isn't right (see Synchronicity post). This research doesn't cost you a thing, so don't hesitate to poke around.
Not too long ago, I had been pestering my wife to get goats. I was getting tired of mowing our half-acre lawn and wanted to find some kind of symbiotic relationship where I wouldn't have to mow. We checked out books from the library, and I read as much as I could about livestock. It took several weeks and many books, but eventually I learned enough to know that I didn't want goats ... I wanted sheep. So began a new cycle of investigation.
Gathering information is an active pursuit. I have found myself researching subjects I never thought I would be interested in. And even if you don't pursue a particular dream, it's fun to learn about new things. It keeps you young, always wondering how things work.
If you are still interested after this preliminary information-gathering stage, ask yourself what other small steps you can take. You don't have to quit your day job to do this. Start small. Are there any continuing education classes offered? Or trips you could do? Are there any people in the local area that are doing what you want to be doing? Call, ask around. People love to talk about what they are interested in.
Don't let not knowing where to start stop you. The resources are out there.
By researching, you have switched from talking about doing, to doing. So don't get down on yourself if you feel like you aren't moving fast enough. This can take some time, but it's all part of the adventure.
Here is a resource to help you would-be inventors (or product developers) get started toward your Dream of the Week:
I've always had a lot of ideas that I thought would make great products, but didn't want to spend the time to start up an entire company. Being a little intimidated by the process, I gave up the thought of ever doing this. And then I learned about Stephen Key who explains how to be a product developer. And what seemed like a huge process was broken down into its simplest form.I encourage you to look for ways to do the same for your dream.