Some other suggestions is never water your plants late in the day, they need to dry off before the sun sets. Also, try to prevent splashing back up onto your plants from the soil. You can do this with an assortment of items from newspapers, to black plastic, mulch, etc. Additionally, try not to plant your plants too close to one another, leave room for air circulation and make sure to pinch off the secondary growths so the plants are not crowded with too much vegetation. One more thing, try to keep the calcium levels up in your soil. If you have had periods where it has rained a lot, the calcium tends to get washed out of the soil. Lastly, do not plant tomatoes in the same spot every year...rotate them.
I have to watch my plants closely, I have a neighbor that keeps planting tomatoes in the same place year after year. I "suggested" to him that this is not a good practice. He complained to me that his yield is diminishing......duh. His plants get nasty looking too.
