If the level of the kayak (while in water) and the dock surface is close (about a foot or so) you can use your paddle to stabilize the boat while you get in. The more equal the dock surface is to the kayak deck the better. This process can work for other surfaces, floating and not, like other boats and floats or some shoreline features like small sea walls.

With the kayak along side the dock, untied, place the paddle on the dock surface, 90 degrees to the kayak's centerline, and on the back deck of the kayak. (Or across the gunwales of an inflatable.)

Place one hand on the paddle shaft, over the dock. The other hand on the on the paddle shaft over the kayak's deck.

No need to wrap fingers around shaft. If you can, grip a bit onto a backrest strap or deck rigging with the kayak side hand.

Put your weight firmly on you hands, this presses the paddle shaft to the dock surface and kayak deck, almost making a bridge or gangway from the dock to the boat.

Shift your butt directly from the dock surface to the kayak seat in one smooth motion. Do not loosen your grip or paddle position until you are in the seat.

Once in the seat bring your paddle around and push gently from the dock.

Right:

Example of these principles applied to Tandem dock entry.

Getting out:

Landing is the same, but in reverse.

Approach dock alongside.

Lift your feet out when ready. Recover your paddle and grab for the bowline to secure your kayak.