New gardeners often make some small mistakes that accumulate over the growing season. These tips will make sure your garden isn't beset by pests or poor growth.
Quality soil and fertilizer is important. Soil full of microbes and earthworms will pay off at harvest time, and organic fertilizers are better at attracting these living things to your garden than chemical varieties. A handful or two of compost will help on this front as well. Make sure it has aged properly, and be sure to apply it a few weeks in advance, as compost needs time to truly become a part of the soil.
Never over-water plants. Read the instructions on the seed package to determine how much moisture is needed for each vegetable type, and how often it should be watered, and trust that just a little more than recommended is not going to help. And remember, an under-watered garden is much easier to salvage than one that has been over-watered.
Finally, when your vegetables start to ripen, keep an eye out for overripe or otherwise unhealthy specimens. These often attract pests, so get rid of them quickly so that vegetables that are still healthy will remain so.