Generally, you'll find a state's court rules in a paperback volume at the end of the state's statutes. Alternatively, check your catalog and/or the online catalog of an academic library in the relevant state for a separate publication. (See "Libraries" to find links.)
Alternatively, use online sources. Many state courts post their rules free on the Internet, and some post even their local rules; you can find links to these rules through WashLaw and/or LLRX's Court Rules, Forms and Dockets database. Otherwise, state court rules are available from Westlaw (xx-RULES) and Lexis.
Alternatively, you can try to (a) get them by calling or going to the court, (b) hire a document retrieval service to pick them up or (c) borrow them from a local academic or county library or (d) get copies from an in-state library.
For a discussion of state court rules, see Fundamentals of Legal Research (West). For more state-specific information, see entries for individual states by name.
To determine the precedential value of unpublished opinions issued by state courts, see "Federal and State Court Rules Governing Publication and Citation of Opinions," 3 Journal of Appellate Practice and Procedure 251 (Spring 2001), updated by "From Anastasoff to Hart to West's Federal Appendix: The Ground Shifts Under Un-Citation Rules," 4 Journal of Appellate Practice and Procedure 1 (Spring 2002).