If your goal is simply to survive, go Communist, as the Soviets will provide a great meat shield on the borders. At that point you could stick with the default templates and be fine. If you go Allied it's unlikely that you'll get help in time, so the strategies are more or less the same as being independent (peace conference issues aside). While there are a couple valid ways of playing, the things I find most useful are cheap piercing (support AA/AT), and a little bit of CAS. As far as template, 20 width pure infantry with support is enough, especially if you're smart about where you choose to defend (in forests, behind rivers, etc.). Doctrine wise Superior Firepower and Grand Battleplan are both viable depending on the support companies/artillery you want to use, and my personal preference is GBP Assault.