If your farm plot is away from your homestead, I recommend setting up a cellar on site and stock it up with fish or something before getting to work. I generally like preparing plot squares of 6x6, but it definitely takes time to clear away trees for the space. I think 36 tiles is the most possible you can prepare at once before the ashes disappear after two days. 3 branches is the minimum needed to start a fire and adjacent tiles are guaranteed to light up. Since preparing plots is heavy work, you can reduce your fatigue by keeping your character naked and have in your inventory only food, a water skin, and a shovel. Your character's warmth status will be sweating because of the ashes, but there currently aren't mechanics that involve moisture.
Turnips are a crop you can maximize with two plantings within a year if you can start the crop early enough, and the Njerp cooking mod boosts their nutrition potential with a roasted turnip recipe. But I guess you might not want to use milk for the mashed turnip recipe. Still, having cattle can help to move the higher yields made possible when your agriculture skill improves enough.
Barley and rye are the grain crops and will be most efficiently processed with a scythe and flail, but if you don't have them by harvest time then any cutting tool and a club will suffice. You can store the harvested Plant (that's the inventory category) indefinitely and won't have to worry about animals eating your crops. But birds can eat your grain Patches, so it helps to set up some traps on the perimeter of your farm or get a dog to scare them away. Sometimes cold weather prevents starting the spring planting soon enough before grain patches wither in the Fall month, but patches come back after withering and you can guarantee spring sprouts by planting a plot in late summer. Another benefit of autumn sowing is that your agriculture skill probably will be higher compared to when you start spring planting. See
this thread for a discussion about calorie yields for flour. You'll see that it's better to avoid planting peas.
Sorrel can be threshed for leaves and seeds, but you can collect it in the wild from hills and mountains. It buffs appetite satisfaction as a seasoning herb and you only need one unit to improve your recipes. Bearpipe is also a useful plant to get your vigor status up when you have tasks you don't want to sleep through.
Hemp is a very handy crop if you get one of the sufficiency mods for weaving, but you might end up planting less since cords typically are used to prepare meat cuts. It still is a relatively nutrition-dense plant and has a higher yield than, for example, clayweed. Seeds can be ground into flour, and you can use hemp leaves as herb filler in the cooking recipes.
Training your herblore skill will help identify unknown mushrooms that can supplement your diet. If you're willing to 'grind' the skill, be sure to collect different herbs at your homestead so you can just pick up the whole bundle each day and use the keyboard shortcuts to examine your food inventory.
Berries have a longer shelf life than meat cuts, but they can still spoil in the cellar. Depending on what kind of berry, the time spent harvesting from a bush can become costly, so don't be in a hurry to harvest them as soon as they're ripe unless you plan to cook a lot. I like using them in the cheese mod, but again I don't know your attitude towards dairy livestock. You'll probably end up using berries to brew kvass for the okroshka soup on the Njerp recipe mod.
But if you do end up going for the cheese mod, I recommend using
Stonelobber's Primitive World Mod for the clay pottery module to keep up with milking a dairy herd. Pot quality matters in cooking, but simply storing seeds in ugly pots won't hurt.
Check the
Plants page on the wiki for nutritional information on herbs. Lake reed can be found at big lakes (bigger than one tile) and you can harvest a lot of it. It's not as nutritious as the grain crops, but you can make flour from the roots.