Paul gave good general advice.
There's so much more that could be said, books written on it, lol.
What is your area like? Are weeds a big issue? If you have good soil and lots of rain, they may be a major factor. If you have lots of time to keep them pulled, it may be fine. If you don't, then weed control of some sort may be in order. My favorite is blocking of some kind. They sell plastic and fabric sheets that are probably easier for a beginner, but I often like to use things like newspaper (many sheets) or cardboard, lay it down and water it, then if you want it to look nice you can cover it with mulch or something that will decompose (leaves) or even gravel or something that doesn't decompose. That will block weeds, give you space to move among the plants, and eventually break down and feed the soil. Some people also get great and very easy results by laying down old strips of carpeting, but I don't know what that adds to the soil, wouldn't want to have to pick it up, etc. It might be good in some cases and and does work WELL.
Prepare your soul well, which means digging it deeply (a tiller is best) and raking out rocks and weeds. Unless your soil is excellent, you probably want to add compost of some kind. Your local county agent may have great info on what local soils need, or nay even provide free testing. Check for county extension - they can be GREAT resources. If you have local farm or feed stores, they can be great resources too, and anything you want to grow from seed will usually be MUCH cheaper there.
Pay attention to how much sunshine the plot gets. If there is any shade, you may have to choose your plants carefully. Then again, if you're in a very hot climate, some shade may be good (most of mine gets light shade half the day from a high oak not far away, and I live in Florida).
Mulch is good for keeping away weeds and keeping in moisture. You might want to consider if you'd like to use a soaker hose when you're setting up if your area is hot or windy - those tend to require more and careful sprinkler watering. Water on the leaves sometimes encourages disease too. Though it can help with some pests. I like to make a mixture of pepper, soap, and water and spray that on leaves to prevent several insect and pest problems.
Put in any supports needed right away. They will grow MUCH FASTER than you expect.
Preparation is MUCH of the key to success. You do have to stay on top of weeds and pests (are rabbits or deer going to be an issue? Or birds, squirrels, etc? There are ways to help with these, but sometimes you can't do anything - depends on your setup.). Checking your plants every day is a good way to head off major trouble (hornworms can devastate tomatoes quickly!).
So much depends on your particular climate and setup. Do pay attention to recommended dates and varieties. And since you're brand new, it's probably better to get some experience with proven varieties. Many of the heirlooms can be fussy, for example, and while the hybrids might not be quite as flavorful, they are usually bred for disease resistance, etc. I actually like to plant several varieties of some things because some years one or the other will do better, and I don't want my whole investment to be the one that fizzles that year.
And some plants have good tricks to know. Like tomatoes, if you're transplanting, it's good to pluck off all but the top couple of sets of leaves and bury the whole plant, stem, roots, and all so there's just a little stem and those leaves sticking up. It makes them look suddenly tiny, but that whole stem will become a root system and build a much stronger plant. Tomatoes also do best with a steady supply but not too much water. Irregular water makes irregular growth, and the tomatoes may crack. Too much water makes them watery-tasting though. I'm going to grow some in buckets this year so I can move them in if we get the rain-every-day that is typical here, because mine have been tasting flat - they give you less tomatoes but MUCH better tasting if they are allowed to almost be wilted.
Some plants gave all those little tricks like that, and some are pretty straightforward. Peppers - I just plant 'em, water, and harvest. If you have a very favorite or two, it might be good to read up on those kinds, and see how to get what you want from them, and then you'll hopefully have a good year and can expand your knowledge the next year and so on.
I know I'm just rambling, and this may sound like a lot of random advice, but these are "things I wish I'd known" at some point.
Actually, see if you can make a friend of someone local who knows all the tricks and can come over sometimes and see how things are going. Such friends are golden.