I've only been hunting turkeys since last year, but so far I've had luck with this setup... took two spring gobblers and one fall gobbler last year. One of my spring gobblers was actually a double header with my buddy next to me getting a young gobbler simultaneously!
I setup usually in a small field on top of a hill, which is about 50 yards across. The turkeys can't generally see my decoys until they crest the hill, and then they're already in gun range.
I array the decoys in a loose V pattern at 15 yards. Two hen decoys (one alert, one feeding), one jake. Usually I put the jake in the middle, closest to me, because the gobblers will typically come in to challenge him. I put the hens essentially facing away from me at slight random angles.
Conventional wisdom says put the jake facing towards you, so that you can get a chance to move your gun into position when the gobbler challenges him nose to nose and turns his fan to you. Also, it helps against falling victim to mistaken identity by another hunter, as the hunter is likely to engage the jake from the side, which would then be facing perpendicular to you.
Those are all good pieces of advice, and for most setups and all other thngs being equal, I would recommend you follow those. But, here's where I depart a bit from conventional wisdom. I hunt on private land with little risk of other hunters crashing the party, and I hunt from a blind. So, I put the jake facing crossways to me. My gun is already in position for the shot as I have it resting on a shooting stick the entire time while I rest comfortably in my lawn chair (yep, it's rough hunting from a blind, lol), so I don't need to worry about forcing the gobbler to turn his fan towards me so that I can move into position. Also, when the gobbler challenges the jake nose to nose and extends his neck, I have a good angle on him to take a shot, because he will be crossways to me. I'm not too worried about the safety issue, because the area as a whole is not hunted much, and I'm in the middle of many farms worth of private land that has clearly marked boundaries, and I know all the neighbours. Even if someone did trespass, I'd see them coming from the top of the hill. I'm generally further uphill from the decoys as well, so chances are that if a shot did come my way, it would hit the hill and not come near me. Plus, they'd likely know that they'd be shooting towards the house and the barns (which are at my back), so there is an added deterrant there, even if they don't spot my blind at the edge of the field.
My situation is very controlled, so I don't recommend my setup in most cases for safety reasons, but for me it has gotten a lot of results. Where I live there is a 25% success rate of getting a turkey based on licenses bought vs. tags reported filled, so I think I'm doing quite a bit better than average getting three birds my first year. I don't attribute all that 100% to the setup, but it helps.
Above all, worry about safety. Figure out what's a safe setup for your situation before you setup.
This year I picked up a JakeMobile and SheMobile combo that I will use, probably with another hen or two. I'll put the SheMobile on the ground in a breeding position just a foot or two in front of JakeMobile. Hoping that will get the gobblers really pissed off lol. I'll report back later on how well it works.
In the area that I've been hunting, there are not a lot of big dominant toms... mostly you see 2-3 year old gobblers. So I am leery to try a full size strut decoy like a Pretty Boy or a B-Mobile. I worry that those will scare off more birds than they attract. Hence the reason I am going to try JakeMobile. I think it will be enough to get them a bit more fired up, without scaring away less dominant birds. We'll see.
Now if the season would just hurry up and start! Seventeen more days... ugh...
Good luck and safe hunting!