Many things go into creating a successful vegetable garden, from water and soil to nutrients. There is, however, one vitally important first step that precedes all of that. You need to select the right seeds for your garden. A number of things go into making those choices; it isn't just about what you want to eat. Match the right seeds to your garden and you will start out ahead of the game.
Choose seeds that are appropriate for your climate zone. All areas of the United States, and many other countries, have rating systems that tell you what climate zone you are in, and the seed packets will tell you what zones they grow best in. Match the two for success.
Choose seeds for varieties that fit your garden. If you don't have a lot of space, choose varieties that are described as "compact" or good for containers. If you don't have room for trellises and tall plants, choose bush varieties of vegetables.
Choose seeds that are dated on the package. They should be packaged for the current season. Anything older will not germinate as reliably.
Choose heirloom seeds if you are interested in saving your own seeds for next season, or if you want to grow interesting, historical varieties. Choose hybrid seeds if you are more interested in reliable production and disease resistance. Choose organic seed if it is important to you to have seeds that haven't been exposed to chemical fertilizers and other chemicals.
Shop online for your seeds for the best variety. Even stores with paper catalogs frequently offer online specials and discounts, or seeds that aren't in their paper catalog.