I had to replace a couple microswitches in my MM last night and the soldering was a real struggle so I'm wondering if anyone has any tips for doing this.

I could solder the diode across the terminals on the bench, so that part was easy. However, soldering the two wires to the NC terminal was a pain as the switches were under the wiring loom so I couldn't do the soldering with the switches screwed down and I ended up awkwardly clamping them to something near by. Even so, it felt like I was one hand short as I needed to hold onto the wires, the solder, and the soldering iron as it seems these wires don't firmly attach to anything as the diode uses the hole in the NC terminal.

Any tips for making this easier?

So you add enough solder to the wires when you're pretinning them so that you don't normally need to add more when soldering them to the terminal, is that right? That would free up that third hand.