I honestly find that playing along to any singer is a really fantastic way to build up a great vibrato and touch. Most vocal lines aren't too difficult, but getting the smoothness of it is incredibly difficult.
Recently I've been working on improving my mixing and mastering - I beefed up my home studio with better microphones, better audio interfaces, and a shit ton of plugins that have really been throwing me for a loop with their quality. I'm throwing it out there - if any Kiwis need help with production, come talk to me! I'd love to help out. I usually work with metal, rock, and alternative, but I've produced orchestral and electronic pieces in the past.