At the risk of sounding like a total newbie (and bear in mind i only started 1st Jan), what is queuing?
Is it a specific thing?
So...what you're doing when you queue is, you're entering a Lay bet that you know won't instantly match, but you're hoping that in the future, the odds will change in your favour and it'll match later on. Because you've entered your Lay bet already, it's sitting in the exchange just waiting for a match.
As mentioned, this is *not* risk free as the odds can drift as well as come in. I only do it sometimes and then only if I can do it with at least an degree of confidence (you know the market you're betting on and have an idea if something is poorly priced and likely to come in). 9/10 of it's fine and I've saved a fortune but I've been on the wrong side of the 1/10 which is considerably less fun.
I have a queue active at the moment for the Basketball. Odds rarely drift to any significant degree in Basketball because you're only betting on win/lose (there is no Draw), however because the games usually take place from Midnight onwards there is very little money in the market early in the evening.
Therefore I've placed my Lay bet in a queue ready for when people come along in a couple of hours. I'm 90% sure it'll match at a price I want, but if it drifts, I'll just re-Lay it and eat the slightly bigger QL.
TBH, queueing isn't something I'd recommend for a new MB'er who might not understand the risks or can't afford the hit to their bankroll (though if a person is new, they will likely only be using small stakes so the QL loss amounts will also be small). It's not something I'd risk a £1000 or even a £100 bet on as then if things do go wrong, you've lost a lot more than just an extra £1.