The New Organic Grower). The key to this is a strong board at the top to support the weight of the plants, and a tight wire at the bottom to tie the strings to. Some people recommend that you tie to the plant at the base, but I find the weight of the plant tends to put a lot of stress on the roots and the stem. I tie to a wire, and things don't get pulled out when the wind blows.
This is what the first row looks like now. Only two more to go.
Other tips on trellising. I like baler twine. It ties well, and it lasts all summer but isn't a problem in the compost of burn pile (depending on your clean-up method and disease pressure). Jute will not make it through the summer. Another thing. Only work tomatoes when they are warm and dry. Early in the morning they are very brittle and will break where you needed them to bend. When the plants are wet from rain or dew it is easy to pass disease from plant to plant. Work when they are dry, and use clean shears (DON"T stick them in the dirt!!!)