Are you having trouble deciding what facility to go for next? Make it the Advanced Warfare Chamber, which has a whole host of benefits. It nearly halves the time you'll have to wait for soldiers to heal, for starters, and there's also the chance it will grant them additional skills when they level up (from other character classes). That can work out in a number of ways, and there's a really good chance it will work in your favor. Try to get that facility early in your campaign to maximize its impact.