I would focus on starting seeds indoors early and putting out large, well developed plants as early as possible. If you put out good sized plants you can get a nice harvest even if you only have June, July, and August for warm weather. If you're growing in the ground you can lay black fabric mulch early in the spring to warm the soil. If growing in pots you can shuffle the plants inside during the cold nights at the end of the year.
You could also use row covers to keep the plants warm during the early Spring and/or fall. You could also try overwintering like shigshwa said. Lots of options, but I would begin with starting seeds early and growing them inside a little longer than people in warmer climates might.