The current meta is very aggressive and tempo based. Let me explain some terms for you since that's a better place to start, in my opinion.
Rogues have a card called "tinkerer's sharp sword oil." It is a 4 mana spell that gives 3 attack to the rogue's weapon, and combo also gives 3 attack to a rogue minion. This present a 6 damage boost for a single turn, and can be even greater than that if Rogues have even more combo pieces. For instance, a turn with deadly poison (2 damage to weapon) tinkerer's oil (6 more damage from weapon + minion) another tinkerer's oil (6 more damage) + blade flurry would be 18 damage from weapon and 7+ from the minion on board. Obviously getting everything set up right is hard, but rogues have lots of card draw, so they can push through and get big bursts of damage out of nowhere.
It is generally good advice for this reason to keep a Rogue's board as clear as possible. Don't let a rogue have a nice minion on board to put tinkerer's oil on.
Zoo warlock refers to a Warlock deck that is very, very heavy on minions. Very few spells, just lots of minions that buff each other and synergize very well. Get tons of minions on board, then combo in knife jugglers (which do 1 damage every time a minion is summoned for the player) and things like abusive sergeants (2/1 minion which gives +2 attack for a turn) and they can get crazy value out of little 1/1 minions all over the place.
"Tempo" decks are decks which rely on acquiring board control and then maintaining it with a relentless pressure of cards. Oil rogue is a tempo deck. There are mage tempo decks as well. Zoo is tempo based. The idea is to get board control then push your advantage relentlessly until the enemy loses. Aggro decks are even more aggressive, and often care very little about board control as long as they can just keep relentlessly pushing damage. "Face hunter" is an example of this; they're fine with you holding control of the board sometimes because all they're doing is punching you in the face with charges and hero power and hoping you can't stop them before you're dead.
