My most important advice is to have the right attitude. Start your first year with this idea: ‘I’m going to stick some seeds in the ground and see what happens’. Don’t put pressure on yourself to attain some self-defined objective such as yield. Make your first year fun; it should be all about observing and learning. Some stuff will grow well and some won’t; get used to the idea. As a gardener, I have done everything correctly yet got lousy harvests; I have done everything wrong and got a bountiful harvest. We can’t control everything. You might as well know up front that gardening teaches patience and humility, so embrace them. Learn to appreciate what your garden gives you, when it gives it to you.
Gardening zones have little relevance for annual vegetables grown in non-winter months. You want to find out your first and last frost dates. Here is one place to find them. Your last frost date gives you an idea when you can reasonably safely start planting cool weather plants. Try some seeds and some nursery transplants. Seed packages and plant tags will have suggested planting times relative to your last frost date.
Find some neighbors who garden so you can pick their brains about when they plant and what grows well for them. Weather, diseases, and pests vary tremendously from region to region.
As for soil, I’m a proponent of making one’s own and putting it in raised boxes ala Square Foot Gardening. If you want to use your existing soil, you have to decide whether to use chemicals or go organic, and proceed accordingly. UMass has a low price and quick turnaround time to get your existing soil tested so you will know what you’re starting with.
My first year of veggie gardening, I just dumped some compost on top of the ground and planted in that. Stuff grew! And I was hooked. Last year I grew 90% of our vegetables, for the year.
Happy gardening.