1. https://www.ancestry.com/ free State Resource Guides: Go to Help, then Support Center, type in “state resource guides”, select US State Resource Guides, then select your state. Gives history and resources.
2. Try http://usgenweb.org/ . This site is all-volunteer. There are volunteers for most counties who are knowledgeable about the area. Each county site is different based on the area and the interests of the genealogists. On the usgenweb map, select your state for info about projects and social media. Then click on the county. The records will not be complete. In many categories people have posted information they have about their families. I have found rural cemetery transcriptions, churches, yearbooks, bibles, etc. I contacted the county coordinator and was put in touch with local people researching my family. Look for info about the country government and records office.
3. https://familysearch.org/wiki/en/United_States_Genealogy: Again you can go to the county level. You will see dates for birth/marriage/death/land/probate. Also a link to the county records office where you will find the hours, rules and available online records.
4. On http://cyndislist.com/ go to the Categories on left, then United States, select your state, select Counties. This website is a catalog of links of all kinds. There will be links to official county offices.
5. https://findagrave.com/: sometimes you will be lucky and find obits.
6. Find the state archives and digital archives.
7. Read books about county history and your local family history.
8. Look for a “mug book”. One series is called Heritage Book. For example: Heritage Book of Onslow County, NC. Salesmen went from county to county to find someone who would coordinate the writing of a substantial book which included family genealogies, historical pictures, churches, social clubs, and whatever they wanted to put into it. Some are available by interlibrary loan. Search http://www.worldcat.org/or https://openlibrary.org/ for the county.
9. Digging Deeper? National Genealogical Society publishes State Research Guides. Go to: http://www.ngsgenealogy.org/ and use the Store tab. The PDF versions are $10-12 and the print versions are $17-19. The print version for my state NC is 44 pages.