Best tip is to do a really good job on the part you started with, about preparing the soil. Good soil makes good veggies!
Re tomatoes, cucumbers, yellow squash, bell peppers, garlic and maybe eggplant
Tomatoes and peppers are usually started indoors and transplanted out. However I start my peppers in late January and my tomatoes in mid February to have them ready to plant mid to late April. With the ground to get ready, I would think for this first time, you would be better off just buying well started plants from a local nursery (better a nursery than a big box). They are not expensive and there's a lot to learn about indoor seed starting, equipment to buy, etc. Once you get the part down about growing the plants, you can work on the indoor seed starting another year.
The cucumbers and squash are easy to grow from seed planted directly in the soil, once the soil is well warmed up, say sometime in May. I've never grown eggplant, so someone else can tell you about what to do with that one.
Garlic is not usually grown from seed, it is VERY slow that way. I usually just take grocery store garlic, divide it in to cloves and plant the cloves. I do that in October and leave them in the ground over the winter and harvest them the following summer. You can plant garlic cloves now, as soon as you get your ground worked, but there's a good chance that by the end of the season, what you will have is one big round, smaller than a head of garlic, but a lot bigger than the clove you planted, but not divided up into cloves.
Tomatoes get to be VERY big plants, 6 or more feet tall and bushy. You will need cages or some system to support the vines. I put 5 of them in a 4'x8' bed and that's crowding them by most people's standards. But 5 tomato plants is probably enough to keep you in tomatoes all season, maybe a couple more if it isn't just you, you have a family.
Peppers you could put about 8 plants in a 4x8 foot bed, but unless you really like peppers you don't necessarily even need that many, I usually do six.
Cucumbers and summer squash are big spreading vines. Two plants is probably plenty for a 4x8 bed. (Starting from seed you would plant a few more than that and then just keep the strongest ones.) There are bush type summer squashes that are a bit more compact, but they are still big plants. But if they work for you, incredibly productive. Two plants might well be all the squash you need. Once they get going, they should be producing several zucchinis a week per plant, maybe even up to one a day per plant. Cucumbers, if you want, can be grown up a trellis. They are similar in size and productivity to the squash.
Make your bed one foot longer and it will divide up neatly into 4 4x8' beds with paths between them.
Best tip number 2: while you are getting your soil ready, start a compost pile! It won't help you for right now, but by fall you will be producing your own home made compost, best soil amendment there is. AND you will have somewhere to put all the weeds you will be pulling, garden trimmings, kitchen scraps, etc, keep it out of the waste stream. If you aren't familiar with composting, we have a whole section on it here, browse around!
Best wishes for your new garden!!
