Essentials
If you want to give yourself the best chance of really good produce you'll need 3 key elements in the right abundance...
Good Soil
Everyone I speak to who seems to know anything about growing decent veg says you have to start with good soil so over the years I've put a lot into the ground I now work and I'll share with you what I've learnt and how I go about it.
Water (and plenty of it)
You also can't grow anything without water. And over the last few years it seems to have been coming all at the wrong time, so water collection is vital. I don't think I've managed to get it right yet. You'll be amazed how much you'll need to collect for a typical springtime drought.
Realism - An Acceptance that not Everything will do Well Every Year
Every vegetable grows best in slightly different conditions, so as a result not everything will grow well each year. There will be successes and failures. Especially when nature throws everything it can at you. Drought, late frost, slugs and snails, caterpillars, couch grass and my plot's nemesis...bindweed. My tip - let it go and just work with, not against, nature.