Catagories???

Can someone please explain to me the catagories on cabins?? How do you know which category is better than the other & where & how do you find that info? Please don't flame me as i've never cruised before & am new to all of this.

Can someone please explain to me the catagories on cabins?? How do you know which category is better than the other & where & how do you find that info? Please don't flame me as i've never cruised before & am new to all of this.

I have cruised many times, and categories have been explained many times, and I still have no clue.

Something about desireable locations plays a part. But, I usually just look at the ship layout, and select what cabin I want and pay no mind to whether it is a D E F or whatever.