You say "plenty of sun, maybe five hours or more". How much more? Five hours of sun would be insufficient for all the veggies that you name. Honestly, the more sun the better, 8 hours is good. Twelve is better.

It was a bad year for most people in the north-east...too many overcast and rainy days.

A lot of people up there rarely had to use supplemental water up there this season. A lot of people also had little to nothing to show for the season.

Actually, I'm not sure how many hours of direct sun. I would guess 6-8 hours. Its overcast today, so I cannot really clock it.

Should I be doing anything now to enrich the soil for next year?

Also, Can I put all my leaves from the trees onto the garden to serve as compost this fall?

Thanks so much for all your advice. I'm so new at this.

There are two problems that usually plague NEWBIES. 1. Overcrowding the plants. They need their own space. 2. frequent shallow watering. This does more harm than good. When the ground dries out, soak it to depth of at least 6 inches. For most folks a soaking once a week is sufficient even in a drought. Be sure to take into account rainfall. Wet roots have more problems than dry roots.
Fertilization is usually a minimal problem, if the other factors are accounted for. Certainly you can get bigger healthier plants with adequate fertilization, most new planters err on the side of over fertilization however. Another problem is compaction, the soil needs to be loose and friable to a minimum depth of 6 inches. The roots need air as well as nutrients and water. Compost and manures do wonders to increase the condition of the soil. The foliar feeds like Miracle grow work for quick fixes, but they are easy to overdo. A granular is better in the long run. There are lots of organic alternatives starting with animal manures, fish byproducts, alfalfa meal etc. They do tend to be more expensive. If you can grind your leaves, they will ok added to the soil over the winter. If not you would be better advised to began a compost bin. Another low cost alternative is to wait until your plants take off next spring, then use them as mulch.

Thanks, Farmerdilla.

I think you nailed it. You named all the things I did. The plants were crowded, and I watered them every other day.
Thanks.