I usually reach for 'till' when a clue reads cultivate and the grid length fits — it’s so painfully common that it’s almost a reflex. 'Till' is tight, clean, and literally means to prepare soil for crops, which is the textbook agricultural meaning that many constructors lean on. In a four-letter slot it shows up constantly in daily puzzles, and because it’s unambiguous (unlike 'cultivate' in the social sense), it’s a safe bet. If crosses confirm T--- or -I-L patterns, my pencil slides right to 'till'.
That said, I also watch for context. If the clue uses cultivate in the sense of developing relationships or skills, then 'foster' or 'nurture' might be a better fit, and those are longer fills constructors sometimes prefer. Short alternatives like 'sow' or 'farm' pop up too: 'sow' is neat for three-letter slots, and 'farm' is another four-letter straightforward fill. When solving, I check verb tense and any enumeration: present-tense cultivate usually points to base verbs like 'till' or 'sow', while past-tense cues could push toward 'tilled' or 'fostered'.
Over the years I’ve learned to treat cultivate as a little crossword shorthand for tilling the earth unless the crossing letters or clue tone suggests otherwise. It’s satisfying how a single word can split into agricultural, social, and metaphorical lanes, and picking the right lane is half the fun. I still get a small thrill when 'till' slots in and the rest of the crossings fall into place.