I dont back into the slip.
1.) lead your forward docking line aft to the cockpit.
2.) Sail in, drop sails at the point where you''ll have enough momentum to coast into the slip.
3.) kick over the fenders, and grab both the fore and aft docking lines.
4.) after turning into your slip, walk to midship and step off onto the edge of the dock, tossing the forward line around the outside section of the outside cleat of the dock, and slowly let it out, till your boat is stoped in the perfect spot, then undo that line, and tie on the aft line, walk forward and tie on the front line.
I''ve found this technique FAR better than having inexperienced friends "help" me with docking, either by stearing the boat (into the dock), or by tying up for me (as my boat goes drifting away from the docks)
To leave, I make sure the rudder is straight, undo the lines, and grabing the shrouds, push her back. as she slips past me, I grab the bow and swing her around, so she''s pointing down the channel, and hop on. Up goes the main, and away I go.
PS. I have the inside slip, right next to the rocks. I also have almost no experience. While I only do this with my little 19 footer, I have a friend who does the same thing with his 38. If we can do this, anyone can.