It has been a long and abundant season for basil, which has enjoyed the warmth. I keep the same plants going all summer by careful picking, pinching off the new shoots every week, or twice a week in hot weather, before they make flower buds. In August, as the plants become larger and thicker, we pinch/cut out some stems in the middle to give new shoots more space to develop, with less overcrowding which otherwise causes leaf rot in damp autumn conditions. The basil pictured ( top left) has given two buckets of leaves every week since June. Lettuce is simpler. Just remove the outer leaves, say weekly, and also remove to compost any leaves that are not edible, plus the weeds and slugs you find.