How to use Twitter: An explanation from a seasoned 17 year old to his newbie 26 year old sister.

I joined Twitter.
Well...let me rephrase: I started using Twitter. I've been a member for over a year and have never even looked at the thing. I just don't get it and it seems like it's just one more social network to keep track of. Still, I bit the bullet - partially to feel like I still know what the heck is going on these days with technology and partially because I'm doing this awesome challenge in February in which the group will have Twitter parties and I want to join in.
(@overcomethelie - check it out, I'm pretty sure you can still join!)
The first person to notice that I joined Twitter was my younger brother, so I immediately 'tweeted' him my ignorance when it came to the social network, and he (like the good brother he is) gave me a few words of advice:
#1 - Go follow a bunch of people. And famous people.
Okay - so this doesn't seem too hard. Just follow people. Like Facebook, or Instagram, or even Pinterest...I can do this thing!
#2 - Tweet dumb stuff and retweet people.
Dumb stuff? Like...what exactly? I browsed a bit while watching the Grammy's and tweeted a few of my first tweets:
I can't believer I missed #TheBachelorWedding (Yup, dumb, got this)
I want a sparkly piano! #Grammys (...oh man, I'm going to be GOOD at this)
Retweet people?

Got this one too!
#3 - Complain and listen to other couples fight.
Jeremy isn't part of the Twitter world...so there won't be any fighting done by us but the 'listening' part I can do. And, as much as I try not to, I'm sure I can manage to complain from time to time.
Does this one make me a Twitter failure?
#5 - People like Twitter Wars.
I'm still not sure what a Twitter war is, but I have a feeling it has a lot to do with #3. Anyone care to explain a 'Twitter War' to me?
As someone who is completely new to this Twitter world, I can see how it can be addicting. I'm pretty sure I could find something to tweet about almost every minute of the day. But...I will try to refrain.
What are your feelings on Twitter? Do you have any advice for a newbie?
P.S. - If you're looking for a quick 'explanation' of Twitter, here is how my brother explained it:
Twitter: Where everyone's opinion is worse than your own.
Haha!
Also, this:

I will never let him live it down...and you should do what he says: follow me!