wicking fabrics use capillary action to "suck up" the moisture off of your skin and spread it over a large area, to maximize the surface area of wet fabric exposed to the air. from there it will evaporate.

base layers should always be form-fitting (tight) to maximize the wicking benefit. You want to layer in the winter because you don't want your wicking layer to be exposed to the wind.... not only do you have cooling by convection (the cold wind), but then you also have evaporative cooling from the sweat evaporating.... needless to say, it will make you VERY cold

you DEFINITELY don't want to be wearing waterproof clothing... because all the moisture will stay inside, which will make you hot initially, but as the water starts pooling it will make you wet, your clothes will stick to your skin, and then the outside air will cool down all that wet fabric....

actually what you should do as soon as you start sweating is open up your jacket for a couple seconds... to let all that moisture escape... it will be cold for a couple secs... but that's a small price to pay compared to just letting everyting get cold and clammy.

bottom line is... EVERYTHING you wear has to be breathable... and if it's not, then you have to make opportunities to get rid of excess moisture...