First make sure you are planning to tie up to a public/state buoy. There are lots of private buoys and owners are not thrilled to find someone on their buoy when they arrive, plus, not all private buoys are well anchored to the seabed. State/BC provincial park buoys have a fee (currently $10 for state) for use and after mooring you should dinghy to shore to fill out a fee envelope then display the stub in your window. In BC's Montague Harbor a park ranger came out in late afternoon to check that people had paid fees and they could pay him directly but he was a lot happier that we had already paid.
I approach the buoy heading into the wind/current so the line attaching it to the bottom is "behind" it from my perspective, hook it with a boat hook and run my 25' bow mooring line, the other end of which is cleated to my bow cleat, through the ring on top of the buoy. Then I walk the line forward and cleat the bitter end to my bow cleat making sure the line is not interfering with bow rails, etc.; that way when I am ready to leave I just uncleat my line and can pull it free from the buoy. A couple of points...make sure you don't snug the buoy right up to your bow, it can/will bang into your hull all night long, leave a little swing room; and, be sure to check both the ring and your mooring line for chafe especially if bad weather is expected. Some people set an anchor alarm when on a buoy just like one would if at anchor. If bad weather is expected I think I would double up the lines to the buoy.