For best flavor, use ripe but firm cherry tomatoes and high-quality mozzarella and olive oil, and keep the components well chilled until just before assembling if you’re preparing these ahead. If making in advance, store the assembled skewers covered in the refrigerator for a few hours and wait to drizzle the balsamic glaze until serving so they stay neat and glossy. You can vary the look and taste by using yellow or mixed-color cherry tomatoes, adding a tiny sprinkle of flaky sea salt on top, or offering extra balsamic glaze and olive oil on the side for guests who like a stronger dressing.