You can tie your boat up to a dock, a pier or a wharf and the terminology is regional, differing from place to place. Usually a wharf runs parallel to the shore, a pier runs perpendicular to the shore, and a dock is a pier where you can, well, dock a boat. The place where a single boat docks is called a slip.
How to dock
When docking, keep three things always in mind: the layout of the dock and other boats, the wind, and the current. Neglecting any one of these, even for a moment, is a recipe for disaster. Plan to use the wind and current, rather than fighting it. This implies that you will generally dock by moving into the wind and/or current, not with it. Look for a flag, or the masthead wind vane on a docked boat, to judge wind speed and direction. Look for eddying around pilings to judge current.You cannot dock too slowly. The reason for this is that you cannot hit the dock, or another boat, too gently. Slow down, using reverse if necessary, until the boat is moving no faster than is needed to maintain steerage way. Do not lose so much headway that you can no longer steer the boat. If the wind or current is moving toward the dock, let it push you in. If it is off the dock, plan to use it in the event that you must head off and try again.
Well before approaching, lay out two dock lines forward, two aft, and two amidships. Have handy also a heaving line of double braid, strong enough to haul the boat but light enough to throw a good distance. Lines should be as long as possible with the understanding that they must not foul the prop and you can heave a line only about 20 feet. Lay out boat hooks forward and aft. Lay out fenders, but do not rig them overboard until you know for certain that you will not need them elsewhere.
Beware of helpers on the dock, even if they are employed at the marina. Having a hand on the dock is of great benefit, but only until they do something unexpected, whether rightly or wrongly.
Remember, also, that you cannot push on a line. If you are going to hit something, you must attach a line on the opposite side of the boat, where you can pull off from that object, or else deploy a fender.
Lastly but most important, when docking, as at all other times, never put any part of your body between the boat and a solid object, be it a piling, the dock, or another boat.
Backing in
At a slip, you can either head in or back in. If you back in, it might be easier to board and disembark directly into or from the cockpit, and it will be easier to leave the dock later. Backing in makes the companionway clearly visible from the dock, on the other hand, reducing privacy both in the cockpit and below.Layout of the boat’s dock cleats might make it difficult to tie up after backing in. Stern dock lines should cross the transom to the opposite side, and thereby place the tugging load more perpendicular to the cleat, rather than tending to pull it up out of the deck, but this might not be possible if the crossed line will chafe against the transom, rail, or fittings.