It is definitely not possible to predict when a germ of an idea will grow to become a strong robust tree. This is similar to business ideas that come in a flash and can be nurtured into a successful start-up and then to an exponentially growing company. But there are some guidelines that should be followed to avoid any financial disaster.
The first factor in this respect is the financial means to get things rolling. Start small preferably with your own savings to avoid interest payouts on loans. Next, keep fixed costs down. Start from a small office in the house and stay away from paying rent. Hire absolutely essential staff to help you out. Reduced expenses on infrastructure initially will help boost savings that can be invested in expansion at a later stage. And most importantly, if it is possible, take a franchise of an established company, pick up the ropes and then branch out on your own.
There are a lot of business ideas that can be fitted in this format. Commercial cleaning is an example. Buy minimum equipment, store them in your house and hire people only if you get a contract for large premises. As your goodwill increases through favourable word of mouth publicity you can invest in fixed assets. If you are especially trained in a particular field like accountancy start with freelance finalisation of accounts for companies before establishing your own firm. Or if you already have an existing family business, try some new innovations and diversification of operations for a quantum leap in turnover.
After all the success of good start-up business ideas is proved in the growth of business.