I fly mostly squishy Interceptors and Phantoms, and have started putting upgrades on them that'll increase their survivability on the table. My weakness is usually HSF builds or anything with turrets and lots of HP. I've not really gone against Decimators just yet but I can imagine 2 of them would be quite scary. Most of the time, I'm against a Falcon built along the lines of MF+C3PO+various upgrades with two other ships, sometimes Bs, Zs, etc.
I've always heard the advice of going for the big ship first, but I cannot see the point of wailing into it while allowing the smaller ships to survive and shoot back. I've always tried to take down the lower-HP ships first, then focus on the Falcon later on. I think I understand the idea of concentrating fire on the big ship while I have my full squad's firepower still available, but I cannot see why I should do it and give the smaller ships 2-4 turns of free shots at my ships.
If someone would kindly explain why I'm such a n00b at this, I'd be very grateful!