Had two leavers in 2 of my first 5 ranked games.

Q_Q

That's why I don't solo queue ranked.

On the subject of runes, is there such as thing as a general rune page that's ok for everyone?

No. But there's general runepage for melee dps and caster, and kind of tank.

You cant just have one for all

Baw. Do junglers have general runes? Or are they character specific?

Junglers are mainly dps with the exception of nunu and fiddle.

Just use caster and dps rune setups.

Hey guys, anybody of you good at Olaf by chance?
If yes, then tell me the right runes and purchase order please!

That depends. Are you playing pure dps Olaf, or a more tanky Olaf? I believe though that for Olaf, Armor Pen Quints are the way to go. That extra armor pen with your passive ult should let you shred through about 40 or so armor right off the bat. Personally, I also use armor pen reds to shred around mid 50's armor.

Olaf is so deceptively strong D:. I usually build him with mallet and warmog then some damage

A good olaf build looks like

Wriggles (please don't lane as olaf)
Zerker greaves/Merc treads (I get zerker greaves cause of his ult)
Frozen Mallet
Atmas
Randuins/Banshees
Youmuu's

Please note: Getting a frozen mallet does not make you an instant killing machine. Olaf's strength lies in many things.
His durability because of his Passive, W, and R. If you can time your W to be up when you're low, then you will get lots of HP back.
A LOT of his damage comes from Q, AND NOT E. However, to do this, you have to pretty much master one technique:

Aiming your axe so you can pick it up and keep throwing, basically spamming 250 damage axes at them every half second - second.
You want to throw your axe so it's basically at your feet or you can run to it while you chase them.

Jungling as olaf is easy.
Armor Yellows
I prefer armor pen reds and quints and mresist/lvl blues, but honestly these are your choice. You could roll with mana/regen and still clear the jungle.

Skill order would be WQWE or WQQE if you think you wont need the extra point in W.

Start at blue golem if you can get a leash or double golems if you can't. From there it's pretty standard jungling route.