Serving the Defendant
You can't start with the law suit until you have effectively served the defendant with the summons and complaint. Depending on the situation, this can be much more difficult that it may seem.
Personal Service. In New York there are, essentially, three ways to serve a human being (as opposed to a corporation). The first, called personal service, is to hand the summons and complaint to defendant. He doesn't actually have to take the documents in his hand. If he refuses to do so, it's enough if the process server touches him with the papers and drops them at his feet
But needless to say, it's hard to effect personal service. Typically, the defendant works in an office and the process server can't get past the receptionist. Or he lives in a building with a doorman, and the process server can't get past the doorman.
Leave and Mail. That's why the second method, called leave-and-mail, is more commonly used. That permits the process service to leave the papers with a person of suitable age and discretion, and then mail the papers to to the defendant. There are some very picayune decisions about whether a doorman or a receptionist is a person of suitable age and discretion. Sometimes, an experienced process server will know about those decisions, but don't count on it.
But leave-and-mail is effective only if the papers are left at the "actual place of business, dwelling place or usual place of abode" of the defendant. So if the papers are left at, say, an apartment that the defendant owns as an investment property, but where he doesn't actually live, the leave-and-mail service is not effective.
Nail-and-Mail. But what do you do if no one at the defendant's residence or place of work will permit you to leave the papers with him. That's where the last method, called leave-and-mail, comes in handy. Where service can't be effected "with due diligence", the process serve is permitted to tape the papers to the door and then mail a copy of the papers to the defendant. As a practical matter, "due diligence" means making three attempts at leave-and-mail.
Service by Publication. What if the defendant has absconded and you can't find him? Under certain circumstances, the court will permit service by publication in a newspaper. For instance, if the dispute involves the defendant's real property, the plaintiff can attach the property and then get court permission to serve the defendant by publishing a notice in the local newspapers. But beware, this involves probably thousands of dollars in advertising costs. It ain't cheap to publish an ad in, say, the Wall Street Journal, for several days on end.
Service Pursuant to the Hague Convention. God help you if your defendant lives overseas. Then, service is governed by "the Convention on the Service Abroad of Judicial and Extrajudicial Documents in Civil or Commercial Matters, more commonly called the Hague Service Convention." That mouthful is typically referred to as the Hague Convention.
And it's a royal pain. Plaintiff has first to have the papers translated into the language at the place of service. Then, the plaintiff has to ask the justice department to send a request to its counter part in the foreign county. The overseas governmental agency then issues the papers to the defendant, and reports on whether the service was effective.
There are companies who specialize in effecting service under the Hague Convention. The last time the Firm did this was many years ago, when it cost its client about $1,000, and took several months to effect good service.