You don't have to be too prescribed, but just mindful of what you want to plant and what's grown there before. Beans, salad and squash family can pretty much be grown anywhere - the ones to watch are brassicas (cabbage family), onion family and solanaceae (potatoes/tomatoes). Be careful with salad (some can be brassica e.g. mustard greens, rocket) and flowers (some can also be brassicas e.g. wall flowers). Radishes are a brassica too so even though they are really convenient for a tiny space maybe choose some salads if you've grown turnips or kale there before.
I like to keep a seasonal plan of what's where but I'm not always good enough to record every detail! We all have our faults - luckily I'm blessed with a good memory.
In my higgledy piggledy patch I like to plant some poppies in between. They love the disturbed soil of the veg patch and I suppose I can loosely argue the seeds are a food source?! They do make the patch look stunning too.