All this being said, I prefer high-quality braided line made for the size of the boat. A rule of thumb is 1/8 inch for about every 9 feet of boat length. We use 5/8-inch braided. I buy different lengths, always with an eye already spliced on one end. The bow line attaches to the very forward cleat via the eye splice. I then tie it off on a cleat and return the line to a cleat halfway back on the bow — 35 feet seems to work well in most cases. For the aft line I use a 15-foot line with a snubber. In this case, the eye is on the aft cleat and goes to a dock cleat with the snubber placed as close to the aft cleat as possible without touching the boat. Then, the aft line returns to the same aft cleat on the boat. For spring lines, I use 15-foot lines. Beyond this, I have at least two other 15-foot-plus lines. All the lines are braided, other than the stranded anchor rode.
A final important note: Whenever you untie from the dock, make sure your lines are secured to avoid a line wrapped around a prop or in the thruster. Ensuring line security can be a temporary delay, but not doing it can cause major damage.