It might seem that suing people or companies is a popular way to elevate your economic status. Why not you?
You may have a legitimate claim against someone or some entity. Perhaps you paid for a product or service you never received. Or maybe a coworker got you fired.
Whatever the case, lawsuits come down to damages: how much is the case worth? Permissible damages vary by the case, but must be provable. In must cases, the starting point is on economic damages (e.g. lost wages, medical expenses). There can be a substantial difference in damages between a medical doctor or a factory worker who misses three months' worth of work.
The other aspect to consider before filing suit - and perhaps a more important consideration - is whether the person or company you sue is collectable. All that a judge can do is give you a judgment, which is little more than a piece of paper saying that someone legally owes you money. From that, you must collect the judgment through legal means such as wage garnishments, liens, or property seizures. To the extent that a person has nothing (e.g. doesn't work, doesn't own a home), you may want to give some thought to filing suit.
This example sums it up: if a person on the street socks you in the face, call the police; if a professional athlete or celebrity hits you, call a lawyer.