I'm not sure you can do much to fix the PP except wait for it to come around.
I started doing something a week or two ago, I started looking at highlights of PP goals scored from around the league, and Most (50%-75% in some nights) of PP goals were scored the following ways:
-Tips and deflections, some of them 'accidental'
-Loose pucks banged into the net from 'scrums' in front of the goalie.
-Screens where there is a LOT of traffic in front of the net
-a good open shot that was only there because SOMEONE on the other team totally lost discipline and started to chase the puck.
So basically, there is not a lot of coaching you can do other than wait for 'puck luck' and just ram basic fundamentals into the heads of your players and hope they listen.
The NHL has figured out how to penalty kill. You set up the 4 man box in your zone, maintain that, and do not chase. You let the team on the PP pass it around the perimeter, wasting time and basically killing off their own penalty before getting frustrated and taking a shot that is easy for your goalie to handle.
So what can you do other than rely 100% on luck? Well you have to be good enough to get into the D-zone and set up. The Leafs are good enough to do that. Beyond that? To try to get more of those deflections and goals from scrums, you NEED to have someone to stand in front of the net and just take punishment. A Dave Andreychuk, Tim Kerr, Rick Vaive type of guy.
Put a guy like that in front of the net and do not have him move. tell him its not his job to skate around with the puck. He's not to just skate by the front of the net, he stands there.
-Eventually the PK might have to 'collapse' that box down lower toward him and that will give your skilled guys on the perimeter more room to use their skill
-It will also provide a non-stop screen and possibly have some shots go in due to the goalie missing them, or be deflected in off of him (or the defender trying to move him out of the way)
-And when a screened goalie gives up a rebound he will be there to bang away at it and hopefully knock it in the net.