Plant a fast-growing squash next to your current crop. Squash sucks nitrogen out of the soil and can help your current crop increase its produce for the season. Summer squash is the fastest growing squash and will use up quite a bit of nitrogen.
Plant calciferous vegetables such as cabbage or broccoli in the fall if the climate permits winter vegetables. These vegetables take up a large amount of nitrogen, so much that they have to be fertilized with extra nitrogen in the average garden, so they will remove the nitrogen over the winter.
Grow sweet corn in the spring if you aren't able to grow anything in the winter. Sweet corn uses a lot of nitrogen and will help you get the balance back in your garden.