Seriously though chelle, there are other wiser heads than me who can give practical advice on it, but I find that there will always be one or two who you just feel drawn to for some inexplicable reason.
Try and pick kittens that are confident, alert and interested in their surroundings. Ask lots of questions - how do they interact with other cats or littermates, people, children or dogs (if known), what do they currently eat, whether or not they will be vaccinated, wormed, neutered and micro-chipped before being re-homed, that sort of thing. Consider whether they're short haired, semi long haired or long haired, as long haired cats will need a regular grooming regime.
Don't allow yourself to be bullied or cozened into making a choice you don't feel comfortable about, and ask if you can handle the kittens you may be genuinely interested in (most rescues will be delighted to let you handle them, provided they aren't in isolation pens or suffering from any behavioural problems).
Above all, have fun!