One secret that few novice gardeners realize is this:
good gardeners kill plants too. Shh. Don’t mention to anyone where you learned this. We don’t talk about it much. We just quickly pull out the dead or dying plants and put others in their place.
Related to the above, don’t plant tomatoes until all danger of frost is gone…at least not unless you’re willing to re-plant tomatoes again.

Zone 4 or 5–you get frost. Frost kills tomato plants. You can do some things to try to keep them warm and alive by watching the weather reports in spring and fall, then when there’s likelihood of frost, cover them with sheets and place gallons of warm water near them. Still, I usually plant tomatoes and then replant tomatoes again every. single. year.
I love herb gardening! Herbs usually grow well. (Sometimes too well!) Most pests leave them alone.
Be careful with mint because it overtakes the garden by both runners and seed.
Sage has pretty blooms and can survive most winters.
Parsley is a bi-anual, so it will come be there again after 1 winter.
Dill has pretty flowers. Both parsley and dill are host plants for butterflies, so save some of the caterpillars and give them to the kids for a science project.