You may get some differing feedback in response to your question.
We have a bouy out in front of our house and like to run over to places like Jarrel Cove which is protected and tie up to one for lunch.
If you are in a strong tide area or at an exposed location and plan to leave the boat or sleep then most folks use two lines both running through the bouy ring and back to the boat.
In most situations though, I use one bow line (I think its 3/4"). I have it rigged so it runs back to the back of the cabin where it is secured. I have installed stainless line guides on both sides of the bow so when I am tied up, the line will not rub on the boat or the base of railing which eliminates ware. I use a marine grade, carabiner with a brass eye at the small end. I think this was around $30 at west marine, but if you are going to use a clip, you want it to have a heavier spring and an eye to keep the line in place. Some will use shock cords. I never have.
With straight line or if using a clip, you want the line to be long enough so you can pull along side the bouy and clip up or run the line through the bouy ring from the cockpit. I tie a knot at the end of the line which keeps the clip from slipping off and acts as a stop as I walk up to the bow.
If you start out with the long line secured in the anchor cleat and the line running around the railing posts, then you just walk to the bow and then bring the end you are holding under the rail on the other side and tie it off. I try to have the bouy about 6-8' away from the hull. This reduces stress if you are bobbing around.