7 × 7 sits between the quick 6 × 6 and the roomier 8 × 8, and it is the daily size on Wednesday, Thursday and Saturday. Most boards split into 6 to 14 patches, many of them one cell wide, and the clues can sit anywhere inside their patch, so a number tells you how big a patch is but not which way it grows.
Most clues show a number; some show only a shape and a few show nothing. If you're warming up, start on the 6 × 6 boards, and when 7 × 7 feels easy, move on to 8 × 8.