Review the section of your state's probate code that enumerates grounds for bringing an objection to the will and, after reading the will carefully, determine whether you have a case. Proof of forgery (someone else signed the will instead of the testator) and fraud (someone deliberately mislead the testator into making will provisions) invalidate a will in every state. Undue influence is a common ground for a will contest; the influence must rise, some courts have said, to the level of substituting someone else's will for the testator's. Procedural issues are straightforward; their substance depends on the requirements for executing a will in your state. If your state requires two witnesses to affirm the will, failure to have two witnesses is a procedural ground for a will challenge.
Learn basic probate procedures about will contests. Visit probate court and ask the clerk for copies of relevant probate statutes and local rules. Use any self-help materials the court provides. Visit the law library and ask the librarian to show you probate form-books for your state. Find out the following: the deadline for bringing an objection to the will, the form the objection must take in your jurisdiction and the appropriate substance for an objection.
Draft an objection to the will in the form and manner required by the probate court. Include standing (your relationship to the testator or the will) as well as grounds for contesting the will. File this document with the probate court before the deadline. The court provides copies of your objection to relevant parties and sets a date for a trial on your challenge. Mark the trial date on your calendar.
Prepare for trial. Gather documents supporting your claims and locate and interview witnesses. Amass as much evidence as possible on every issue you raise. Your specific claims dictate the type of evidence required to carry the point. Organize your claims and practice presenting them.
Appear in probate court the day of trial. Make sure your witnesses appear as well. Present your arguments to the court and offer evidence to support each point. Convince the court that your objection is valid.