While chasing down a dim headlight issue in the MGB, I was reminded by ace British car restorer and top wrench Mike Darby that auto electricity likes clean connections. Be they grounding points, bullet connectors or light bulb holders, a clean connection is a bright one.
The dim light problem was greatly improved with a thorough cleaning of all the connections from the fuse block to the headlights themselves. The 'B's headlights are still not blazing - especially by modern standards - I can see and be seen much better now.
One tip I've read about over the years is to make sure the fuse clips in the fuse block are clean, too. Rolling a piece of emery cloth helped but a walk down a random aisle in the local big box discounter brought me to the gun cleaning tools. On the peg were several brass bristle brushes used to clean the bore of various firearms. I picked up one that looked like a good fit for the fuse clip and paid my $4.00.
It works perfectly. I even put the brush in a cordless drill and found enough maneuvering room to automate the clip cleaning process. And with only four fuses, the process didn't take long at all.