Adjustment: if you're someone who can nap, do so the afternoon before you go to work. The longer you can sleep, the better.
-----If you can't nap, then just stay up all night and ensure you moderate your caffeine/sugar/whatever intake throughout the night. Don't drink five coffees in the first hour, even if you think you need it to get past midnight! You'll be dead by "lunch".
-----Be VERY aware of your ability to drive home the first few days. I was usually good the first day or two during shiftwork, but would be dangerous on the drive home by the third and fourth day. I'm not sure why, but this was my pattern. I honestly could have killed myself a few times, and should have napped in my car before attempting to drive home, I was so tired. These were 12 hr days, 7 days/week types of shiftwork, so it's a bit extreme, but you should expect a similar response from your body, especially if you've never been on 3rd shift.
Sleeping: I either wrapped a pillow-case over my eyes or had a sleep mask. I didn't want to black out the room, because it's nice to take the mask off and have natural sunlight wake you up when your alarm goes off, and not have the urge, like early 1st shift days, to hit the snooze 100 times. Like 1st shift, this depends on time of year and DST, of course, but it works very well in the summer. BAM! Bright light and I'm up at 1600, ready to do whatever.
Off days: I wouldn't suggest that you try to readjust on your off days. You'll feel off during your days off and will be a zombie again for the first night (at least) when you go back to work. Stick with a 3rd shift schedule, as best you can.
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When I was single, I loved 2nd shift, and often volunteered for it when we went into period of shift work. The added shift pay differential didn't hurt either!
Once I had my first baby, 3rd shift was great, even though it was only four six weeks or so. I was also taking an online course that required a lot of reading, so coming home at 08-0900 and reading for a few hours before going to bed was manageable, not to mention the at-work reading I was able to do when things were slow, since, unlike first shift, the place was a ghost-town (i.e., I didn't need to pretend to be busy when things were dead, and was able to stay alert by studying - awesome perk!)
When I woke up in the afternoon, it was to eat dinner and spend another couple of hours with my family before heading off to work. I considered this another benefit, since I was waking up fresh, spending time more alert and happier with my family, instead of being a zombie, which would be my state after many first shift days.
Finally, there were fewer "managers" around during 3rd shift, so things were ALWAYS more productive! For minor complications, people are usually more apt to find the answer themselves than wake up a supervisor in the middle of the night. During first shift, having multiple supervisors only a phone call away means more stopped time and more people second-guessing your decisions (sometimes.) The way our business sometimes worked, is that 1st shift would debate over how best to more forward through a problem, second shift would try to sell it to the higher-ups and then prepare for it, then 3rd shift, with fewer people involved, would get it done, usually without any need for the help of higher-ups. We were able to figure it out and find a path forward through almost every minor roadblock, instead of coming to a full stop!
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Sorry, that was long. I guess I mean to say that, for a young man or someone who wants to keep a somewhat normal sleep schedule, 1st or 2nd shift is best. For someone who has a family, especially with two working parents, 3rd shift works out logistically (though you never get to sleep with your wife, except for your days off - that can be exciting, like dating again!!!)
