Know who you are suing. What is the Defendant's name and address? Is the Defendant a corporation?
Or is the Defendant married? Find out before you go to the court to file this action. You can look up corporations at the Secretary of State's website. Ownership of property is public information. Your assessor treasurer will be able to provide you with the information you need to name the correct defendant(s). If you do not know if the defendant is married, you can sue them by name, and add the words "and spouse, and the marital community composed thereof".
What is the basis of your suit?
This guide is for getting your deposit back after a residential tenancy. The basis of your request for relief is RCW 59 18 260, RCW 59 18 270, and RCW 59 18 280. Look them up. See exactly what they say.
Arrange for service of process on the defendant
You cannot serve your own process personally. Hire a server, or have a friend do it. Corporations always have a registered agent who has to accept service of process on the defendant. In small claims when a residential tenancy is the basis for the suit, service can be done by certified mail sent to the same address where you paid your rent. When there is any question, pay a process server and have them file an affidavit of service.
File the action in the correct court
The correct court for a suit based on a residential tenancy is the county where the tenancy was located. If the apartment or the house was in county XXX, then that is where you file the suit. There is a fee to file this and you'll have to pay the server; these are costs and you ask the Court to award you this money in addition to the judgment you are seeking.
The court will tell you when to come back for your trial or mediation date.
If you don't show up the case will be dismissed. If you have properly served the defendant and have filed proof of service and the defendant doesn't show up the court will either reschedule or enter a default judgment against the defendants. A default is where the plaintiff gets what they asked for because the defendant didn't show up as ordered.
See if you can reach an agreement in mediation
If you are right and the other party is just being stubborn, hold your ground. You don't have to give in, although there are benefits to reaching a compromise.
If you can't agree, get ready to try your case.
Go watch a docket of small claims - it is free and very entertaining. You will learn a lot from watching other litigants. Prepare your case by organizing a copy of your complaint, and the documentary evidence that supports your allegations, and printed copies of the relevant statutes and possibly caselaw. In a residential deposit case, your evidence is the contract, the walk through checklist, maybe some photographs, invoices and payment documents - in other words, other papers that support your case. Once you have one "original" of all your documents, make three copies - one for the judge, one for the other party, and one for you. Your "originals" will go to the clerk to be entered in the court file. 3-ring binders and index sheets are a great way to organize this material and make it easy and simple for the court to review. Dress up for court. Be respectful and polite and never, ever lose your cool. Never, ever interrupt a judge, and be nice to the clerks.
The court can award you a judgment, but cannot collect the judgment
Collection is a problem for an attorney. If the defendant doesn't pay the money as ordered by the Court, ask for help from a collections attorney.