Normally I take my position according to the phasing of the lights. There's nothing worse than arriving at the lights and unclipping and they go green as you put your foot down. If I haven't seen them go red and/or don't know how long they will be red I'm cautious. I'm looking for a slightly larger gap between cars. or a slightly slower vehicle to pop in front of.
Also uphill vs downhill, I'll go further up the queue if it is downhill and I'll be well away. Pinch point ahead? I'll take more care. Every queue is different. Even if I know the lights, the cars and drivers are different. I observe and make my decision from what I see.
If an arse has cut me up I'll go in front of them. Foolish, but fun.