Gardening is my life and my sanity (well, chickens and bees, too). I grew up in the garden and have had my own for almost 20 years now. Here are some observations, some obvious, some not.
One of the easiest books to work with, and just so happens to use raised beds, is Square Foot Gardening. Very easy to understand and start. And there's really no reason not to start now. You have time to get in several successions of lettuce and radishes, if you want. You could probably get a nice crop of chard as well and I was just reading about winter radishes somewhere. Just have fun with it. And remember, it's better to start small, and wish you had more, than to start too big and not be able to keep up with it.
You don't have to start from seed, but you'll definately have way more choices if you do. I used to always start with seedlings from the nursery, but when I actually saw the variety of stuff you can only get through seeds, I didn't have to think long before I switched.
Weeds can be a problem, but I've actually really come to enjoy the time I spend pulling them. You just have to get into it. It's just another reason to spend time in one of my favorite places, outdoors. Mulch helps but they still come up. I also put my seeds in pretty close together, usually a hair closer than is recommended, so weeds have less room to come in. I know folks say not to throw the weeds into your compost, but unless you're dealing with pig weed or something noxious and hateful like that, I don't worry about it too much. It depends on how hot your compost gets and how long you let it sit.
Here's a hint if you start sowing seeds directly in the garden. It can be difficult, when starting from seed, to distinguish the things you planted from a weed. Until, you learn the difference, don't be afraid to leave a weed alone until you're sure it's a weed. It really sucks when you realize that you weeded out the pumpkins and left the pokeweed to grow. Trust me, you can only eat so much poke salat before you just get depressed about the whole thing.
As far as amendments to your soil, hey, you're on the BackYardChicken Forum. Hmmm, what shall we use, what shall we use? I'll give you a huge hint, it comes from your chickens' butts and it isn't eggs. If you're not going to plant anything now, you can add it directly to the soil, if you are, you should probably let it age a couple of weeks first. Amending your soil can make the worst clay into wonderful, fertile garden space. In addition to the litter from the coop and compost I also use kelp and fish emulsion to amend my garden soil. . . every year. When your soil is good, your plants are stronger and you'll have fewer pest problems. Most insects that can't be picked off, can be discouraged with a simple garlic/pepper (grind up 1 small onion, 4-8 gloves of garlic, and a Tbs of dried cayenne with a cup or two of water in the blender, strain, and put in a spray bottle) spray.
Above all, have fun and plant what you like to eat. I used to plant celery and okra (I can't stand either) and every year, I hoped they'd just die before I had to harvest them. Finally, it occured to me to just not plant them. If it's not fun and you don't eat what you grow, you won't keep it up, and that would just be a shame.
Mark
PS Oh yeah, learn to can, get a dehydrator, and stock up on freezer bags. Not only will you inevitably plant more than you can eat, when you learn to preserve your fresh garden produce, it can feed you all year long.