1.  Never approach anything faster than you want to hit it.
2.  It is better to hit something at 1 knot than 3 knots.
3.  It is almost always better to hit a piling than another boat (And usually cheaper)
4. If your boat is doing what you want it to do, don't change anything, you will eventually get to where you want to be.
5. If you feel you are going fast enough to make the dock, then you are probably going too fast.
6. Pilings are your friends.  Never be afraid to use a piling as a pivoting aid (As long as there are no objects sticking out of the piling, which might damage your boat).  Pilings and rub rails were made to go together.
7. It is far - far easer to add a little power when needed,  than to take off too much power once added.
8. The water can never get too flat to scare me.
9. It is better to be on shore wishing you were at sea, than at sea wishing you were on shore.
10. Your docking skills are indirectly proportional to the number of people watching.
11. Never try to fend off a boat with a human fender, fiberglass does not cry, does not bleed and is a lot easier to repair than broken bones.  (Have the person(s) who will be helping with dock lines carry a fender, which can be placed at critical locations during critical times.) 
12. You don't have to dock the first time you enter the marina.  Sometimes it is better to get an idea of what the wind and current are doing, then exit the marina and reenter with a plan.
13. If you are having a hard time backing into a slip, pull in bow first.  Nothing says you have to enter stern first, unless it is necessary because of shore power hook-up.
14. If you can't dock in a slip because of weather conditions, tie up on a T-head and wait until the weather changes.
15. If you are assigned a transient slip in which you feel uneasy about docking, ask the marina for another assignment.  It's your money (And boat).
16. If you find yourself in a situation in which you just don't know what to do, it may be better to take the boat out of gear and gather your thoughts, than to try and power your way out.  Remember it is better to drift into a piling or another boat, than to hit one at 3 or 4 knots.  (This also gives your crew time to get a fender to the critical locations.)
17. Boats always shrink when they are put in the water.
18. A marine head (toilet) is not the same as the one in your home or office, if it gets plugged you must take it apart to unplug it, plunging does not work.  So, as I tell my guests; "Other than "TP" which I supply, if it didn't go in your body by way of your mouth, it doesn't go into the head (toilet)."

Safe and happy boating

Remember, your are not alone.  Most boaters who have been boating very long have found themselves in an occasional position of embarrassment while docking. A large number of them have probably dinged a boat or two, or run aground, or both.