I just saw your thread in OC&D, and think I might be able to help you.
Now, I don't personally play Netball, but I do know something about personal fitness.
Firstly, a large part of getting into running is just sticking with it.
Try to remember your goals and why you're working toward them when you are feeling demotivated.
Another trick is to write out a list of small, short-term, goals that you can cross out as you finish. Believe it or not it works really well.
Aside from just keeping to a set schedule or running to get it done, try to put yourself in a happy, "let's do this thing!!" kinda mood.
As for a rockin' playlist, i'm not so sure i'll be amazingly helpful here since everybody has different opinions, but i'll tell you some songs that always get me pumped up.
~Sum 41 - Fat Lip
~Panic! At The Disco - That Green Gentleman (Things Have Changed)
~Ugly Duckling - Smack
~XV - Awesome
~Blue October - Jump Rope
~Foxy Shazam - Oh Lord
~My Chemical Romance - Na Na Na (Na Na Na Na Na Na Na)
~The Offspring - Slim Pickens Does The Right Thing And Rides The Bomb To Hell
~Falling In Reverse - I'm Not A Vampire
~AFI - Beautiful Theives
~Santana - I Am Somebody
~Cage The Elephant - In One Ear
~Gaelic Storm - One More Day Above The Roses
~Imagine Dragons - I'm On Top Of The World
~The Virginmarys - Dead Man's Shoes
I tried to keep it mostly upbeat stuff, I can find more if you want.
On a side note, OC&D is generally politics, religion, and debating (which means everybody starts acting like an ass) so next time you've got a question like that you should ask it in the discussion thread. It's stickied.