It's a tough call, but my advice it to just pick one and get started. You simply won't know what works or what doesn't until you start working with your ideas and seeing if they are useful and of value to your customers. Whatever you choose, make sure you have a passion, drive and enthusiasm for it, or at least a passion and drive to see what works and what doesn't. Also know it's rare that your first business will be a success straight out of the gate. Give yourself seven to 10 years to...