As the game starts up hold the back button on your controller. Look at the Xs next to the names(that normally show when someone is dead) and whoever does not have an X is the host. Sometimes more than 1 person will not have an X. Usually this means they are on the same box or internet connection.
In the game you can have your team press right on the D pad and see who on your team gets a blue border around their icon. That person is host.
You can try grenade jumping. If you gain some extra air then you are host.
You can comitt suicide and look down. Host will see a torso, everyone else will not(I could have this backwards).
What I do:
1. Try to get host, wait for it to go to 2 within the first 3 seconds of searching and display the empty player slots.
2. Beforehand, have someone press B in pregame lobby, the start the game. This brings up the leave lobby box and will allow you to get out of a game should you get "Locked in"(which means it goes to 3 without you being host).
IF I am standbyed in a CTF
If the opponent does primary on me in a ctf, I have no problems cheating back with secondary. It sometimes works but they can stop it only if they know how and realize it is happening. This is also known as client standby. It resembles the dummy glitch but can be done by yourself and with no warthog. I wont go into detail on how to do it, but if you know how, that is an option vs CTF standbyers.
Alternatively, if my team has host and they do dummy or secondary, I will secondary or primary standby back to win the game.
And yes of course I realize I COULD be suspended for this but it has yet to happen. I assume because cheaters do not like to leave feedback drawing attention to the game in which they cheated aswell.
SLAYER
In a slayer game, 1 guy(host) must do all of the work. With that said, if you gain an early lead, have all but your best player quit out. This makes it harder for that one guy to find your 1 guy and you are free to hide. If you don't have a good enough hiding spot, you can play with slightly better chances and just try killing the 3 non-host enemies.
ASSAULT
If I am about to go somewhere or it is late I will just hide the bomb and sleep on it. There is the chance that they wont find you and they will just quit out. In zzbar I go either in the palm tree between the seawall and the water(by jumping off the other, less leafy tree) or I go to the top of the base via the shutter things then knock them down. You can also jump off someones head on the wall thing at the top of the base stairs.
If you can manage this, it is the best thing to do. Take a ghost and go to the invisibarrier by the water(the side opposite the bomb spawn) and park the tail of the ghostagainst the rocks. Then park a warthog on top of the ghost on the left against the wall and on the right. Have a guy get in and out of the ghost and he goes through the wall. Throw the bomb against the wall and have him grab it. Then have him walk along the wall to the opposite side and hide behind the bump in the tan wall