In reply to tomtom89:
Good advice from others (and Welsh Kate knows her stuff).
Other things I used to look for/asked about when I sat in on interviews/hill days during my spell in MR:
- Availability. It doesn't matter if you're a mountain god if you're never available for the callouts themselves, plus a hefty amount of training and fundraising event commitment too
- Support of family and employer. If they aren't happy with you sodding off onto the moors at weird hours then your time in MR might be short-lived
- Motivation. Don't be the guy who (when asked why he wanted to join) replied with "I want to be able to shout at those people who make stupid mistakes on the mountains"*
- Good fitness and being able to be comfortable in a mountain environment. You don't have to be Kilian Jornet but a full day in poor conditions with a 10-12kg pack shouldn't be too much of a stretch.
- Good nav skills. If you can give a six-figure grid for your location at any time, day or night then you're already at roughly the right level
- Be aware that it's a volunteer team performing a serious role. Sometimes it's a petty world of infighting and fiefdoms, at other times it's lifesaving in wild and remote places working as a cog in a well-oiled machine. The rest of the time it's somewhere between a climbing club (with extra morphine and stretchers) and the Rotary Club. MR is weird and wonderful and you won't see all aspects of the above until you have been there for a few years.
Each team is different, with a different culture, structure and even an approach to how recruitment and training periods work. Keep your ears and eyes open, ask questions, be honest about your abilities/motivations and interact with the other team members and prospective recruits.
*Not joking.