I don't have a preconceived idea other than what I know has worked well or poorly for me in the past. It's not binding, but I know that odds are I'm not going to start off in an EGR triple. I know that as G or A, I'm not likely to immediately go after the other. I tend to like EF and RT alliances if I'm playing one of those powers, but everything is open at the start of a game.
In early press, I'm looking for allies who seem intelligent and have a plan. Not just the standard blah blah let's work together, but something more concrete that shows me they have really thought about working with me and why that is their best course.
I like early dogpiles -- on France, on Austria, on Turkey, wherever. I don't initially strive for them, but if that seems to be the mood, I will fan that flame. It may not be quite as good as a solid two-power alliance out the gate, but better to pile on than be piled on.
I like quantity and quality of press. If I have a strong ally, we're going to be exchanging lots of press at all hours. If someone only logs in once or twice per phase (especially in the early turns) and gives vanilla press, they probably will be a target rather than an ally.