im sorta new to wow and i would like to be a tank. people keep telling me to get more aggro. what does it mean and how can i get more of it? also, any tips on being a good tank will be much appreciated

One thing I notice with new tanks is if something is attacking one of the other group members the new tank ignores them and just keeps hitting on his target vs trying to pull the baddie off of let's say the healer. Just try to pay attention to to who is getting hit and grab agro back if possible.

There are abilities, specifically talents that make you get more aggro, basically it is how willing the monsters are to target you over members of your party. Every tank class has abilities that you spam the cd on in order to keep your aggro up, there are also (or use to be ) addons that have a chart for aggro much like the damage meters.