Bonanza 35 pilot reported a fuel starvation event resulting in the engine shutting down. The pilot reported failing to switch tanks during cruise. The pilot performed an off airport forced landing.

Narrative

Local flight at home field ended in an off-airport forced landing about five miles short of the intended landing runway. Plan was to practice two GPS approach procedures. Single pilot; no hood; no safety pilot; totally VFR; just perform two GPS approach procedures to practice setting up and using the fairly new to me panel mounted GPS. Planned about an hour flying; departed with slightly under half-full tanks on both sides; about 1:15 available on each side tank. Finished the two approaches and decided to do one more short one without starting all the way to the initial fix; just to practice the descent on the GPS glide slope.Descending with gear down; the engine quit about five miles from the runway. Saw immediately the selected left tank was empty. I had forgotten to switch tanks about half-way through the flight as intended. There was still just under half tank showing in the right tank. Switched to the right tank promptly expecting an immediate restart; but the engine did not restart. Tried everything I could think of to try to restart the engine with no success. Finally at about 500 feet AGL I called and landed in what appeared to be the smoothest desert terrain straight ahead. The landing was surprisingly uneventful and even the fairly short run after landing was surprisingly smooth. However the aircraft hit several cactus along the way. The call had the airport's fire department on the way immediately. Uninjured and surprisingly calm I inspected the aircraft and found medium size dents on the right wing and nose cowl; small dents on the side of the engine compartment and on the left wing and landing gear door. The tachometer showed 1.2 hours for the flight.The FAA from the nearest FSDO inspected the aircraft the next day and recovery procedures are underway now two days after the event.My mistakes were forgetting to switch tanks; departing with legal reserve but still minimal fuel; and possibly not thinking under pressure of everything I should have done to restart. Regular practice of these procedures would be a very good idea but hard to prioritize when you fly for hundreds or even thousands of hours without incident. Perhaps insisting on such practice at every flight review would be a good idea.