Find the USDA hardiness zone for your area using the zone finder at the National Gardening Association website. Once you know your hardiness zone, you will have a better idea of how long the growing season is for your garden plants.
Visit your local garden center and look at the seeds offered. Generally, if you shop for your seeds locally, the seed selection will be for plants that will easily grow and thrive in your area. This doesn't mean you shouldn't try growing plants from seeds that are unusual or atypical for your area --- just realize those seeds and plants may take more care.
Read all the information on the seed package. The package should have a date stamp so you know the seeds are from the current year and will, therefore, germinate more successfully. Also, you will discover germination time, days to maturity, soil and sun requirements. All this information will help you decide if the particular seed is suited for your garden. You may also discover that certain seeds will need to be started indoors, weeks before that last frost in your area, in order to mature successfully during your growing season.