Alright, so i bought 2 extra rune pages giving me 4 and dont know what to do with all 4.
i was thinking one for AP, one for AD and one for a Tank, but dont know what to do with the last one... any ideas?

Go for lane positions according to what kind of champs you have. If you have lots of AD-based toplaners, then build a toplaner page with AD/APen marks/quints and defensive seals/glyphs. If you have lots of AP-based toplaners, then use AP/MPen marks/quints instead. You'll have to leave one role out, but you can compensate by using your top-lane page for either mid or bot, depending on what kinda champs you have. That will leave you with 2 pages: one for jungling and one for supporting.

EDIT: If you have an arranged team and you know what role you're playing, then you can pick runes according to matchups. LIke if you're top-lane, you can pick up specialized runesets for AP vs. AD, AD vs. AD, AP vs. AP, and AD vs. AP.

Make ur rune pages based on what u play.

I would say u shud have a page of AP, one for Tanky bruiser, one for support, and the last shud be a specialized page for a certain champ u enjoy playing.

You shud adjust ur pages when u get higher elo, since ur gameplay/style will change.