Are we talking about piled slips, or a finger float or dock? If it's a finger float/dock are you on the upwind or downwind side?
In the past we've had better luck backing in with speed from downwind (docking on the windward side of the finger) The turn tends to swing the bow upwind, of course, and then once in the slip you should have good "brakes" in fwd gear and the wind holds you on the dock. Often all you need do is quickly secure a sternline and the wind will do the rest.
If you're docking on the leeward side the same technique works but you need to get lines on in a hurry. I've seen people use a modified grapple hook to snag a bullrail or a cleat to help attach to the dock more quickly.
But you have to be a bit bold and do this with speed and good steerageway. It helps a lot if your boat backs well and predictably (which many do not)
".. there is much you could do at sea with common sense.. and very little you could do without it.."
Capt G E Ericson (from "The Cruel Sea" by Nicholas Monsarrat)
1984 Fast/Nicholson 345 "FastForward"