To start with, he said that here in the Pacific Northwest, we can pretty much plant things year round. It's good to have succession planting, so that the dirt can have different nutrients added and taken out of it, and it also reduces pests. This also gives us a more complete use of our land. Some cool season crops he listed were root vegetables (beets, carrots, parsnips), lettuces, snow peas, and brassicas (see here!):
There are also many things we can use to cover the ground or our plants to make them survive better. He recommended these wall o'water tubes for tomatoes, (and other hot weather veggies, like eggplant and peppers) just so you can put them out a little earlier and give them some more growing time. I've used these before, and they work really well; especially when it's colder outside than you want it to be. The easiest way to use them is to put them around an empty 5-gallon bucket that's upside down over your plant, then fill them with water from a hose, and carefully remove the bucket. If you get a really hot day, you want to check your wall o'waters just to make sure the top is open and your plant isn't cooking inside there! When the plants grow over the tops (like below) it's probably a good time to take them off.
Bill also talked about floating row covers (a thin white fabric that you use to cover your ground/seeds; it also lets in light and water though) and using mulch to keep down weeds and protect your soil. The row cover also wards off bugs, increases the soil temperature, and protects from any late freezes that might happen.
For overwintering plants, one of the best things that you can get or make is a cold frame. This lets in light, keeps out some of the cold, and keeps out pests (unless they're in there in the first place!) He recommended using a cold frame over a raised bed; particularly if the bed was made from stone- the rock will draw in and retain more heat, but also it prevents the wood of the frame itself from rotting. You can leave them open on the top once it's warmer out, then close them again at night.
This is a hoop house; easily constructed with some PVC pipe and plastic sheeting over whereever you are already growing things.
You want to make sure that your cold-weather sites have a few desirable traits that will help things grow better. Your site should be protected (maybe close to your house or some trees), accessible (so you can actually get in there), and have good drainage.
Next up, what to plant and when!!