Welcome to PvP!
Rule #1 - you cannot control your teammates. You can only try to entice them into actions by asking nicely. Then you say a little prayer and hope it happens.
Rule #2 - Play conservatively until you begin to see when you can play more aggressively.
Rule #3 - Stay at low tiers until you start to feel the difference. Tiers 2-4 truly are training tiers and you will even get a mix of bots / players to help ease you into the new mode.
Rule #4 - Re-read Rule #1
Rule #5 - Don't get upset. Bots do stupid things because they are bots. Humans do stupid things simply because they feast on your misery. Steel yourself, captain!
Rule #6 - Destroyers live and die by their concealment. Bot DD's just go forward, but human DD's will stand-off with you and you need to know when they spot you vs when you spot them.
Rule #7 - Don't be broadside in your cruiser. Bots don't shoot well - people do. Try and go dark before you make your "Gamer Turn" in front of hungry humans.
Rule #8 - Your BB likes to burn. If there's even a chance that your side is going to get pushed, be ready to turn away and "kite" so that you don't get stuck and burned down.
Rule #9 - Re-read Rule #4
Rule #10 - The matchmaker is purely random - given enough time the less-skilled players will be on the enemy team just as often as they are on your team.