Tips for American cruisers (more specifically the Boise)?

I find myself getting consistently bootied on by Battleships and other cruisers, more specifically the German cruisers which are essentially just mini BB's. I find myself outranged and outgunned nearly every time I play. And I always find myself in games where everyone is a tier or two higher, which only further cements my destruction. I'm not sure what I'm doing wrong I press up with my team, sit behind islands when necessary hit my shots (mostly) yet I still stink. I do fine with BB and DD just not Cruisers. Also what's up with all the lobbies full of BB's? What do I do against them?