Sign 1: You have money to invest and some in savings
It takes more than just a dream to make a business happen. Traditionally, you need to have startup capital, and you should also have some cash set aside in savings for your personal 'financial runway.' This step is crucial, and it might mean you need launch when you feel you have enough money saved up.
Sign 2: You can't imagine doing anything else
It sounds great to own a business and be your own boss, but you still have people to answer to when you set off on your own. You basically have several bosses, just not a traditional boss. If you are unhappy in your current career, and truly can't imagine being happy doing anything other than starting your own business doing what you love, then follow your instincts. But don't start a business just to avoid having a boss. There's plenty of happier companies that will allow you to spend time with them and pay your bills if you spend all of your waking hours at work and thinking about work.
Sign 3: You have either a well-thought out business plan or you make decisions faster than anyone you know.
If you haven't thought past the first year of your business, it's time to take a step back before jumping in feet first. And yes this is relevant for those who can make decisions quickly, too. To succeed as an entrepreneur, you need to have a well-thought out plan for the present and the future. Some people make a plan with a 30 page business plan (please don't ever make one longer that); others make a plan with 3 sales channels in their head and have already pitched 5 clients with a 1 page .pdf). Think about the growth of your business as well as whether you want to stay in one area or branch out regionally or nationally. Having a clear plan in place is a sign that you're ready to start your own business.
Starting a business can be scary, but it is also exhilarating. There is never going to be a perfect time to start out on your own, but having money and a plan will go a long way toward turning your dream into a successful reality. Otherwise, you can keep working for the man. Those of us that take the risk will go ahead and become that man (or woman) ;)
Apply to the Handshakin Pre-accelerator to launch your business today.