It's hard in Texas, where there's no public land. I've had very good luck in/near cemeteries, behind VFW halls and Volunteer Fire Department buildings. Churches are an option, but I've never been near one when it was time to pick a spot for the night.

Get in late and leave early. Watch out for greenbriar and poison oak/ivy. Avoid rest areas, dead-end gravel roads where kids might go drink and fool around and climbing fences. Don't unpack more than you need to bed down and sleep.

Be prepared to lose some sleep to nervousness the first night or two. Know that it gets easier as you (successfully) do it more.