The easiest way is if you have an existing account with a few toons on it.
Say you have a Warrior, Rogue and Mage.
Call the existing account.. A.

You buy 4 new accounts.
You chain link from A like this.

a -- b -- c -- d -- e

B still gets RAF bonus, because they're linked to C.

When E grants levels to D, D can even use those granted levels to grant to C. Etc.

So take an existing toon on A, the higher the better.
AoE classes are superb, as are tank types.

Put your group into an instance, leave them near the zone in.
Pull a lot of mobs at once, as many as you can handle.
Kill them fairly close to the zone in.
Move the group up to the deepest safe point.
Pull a lot of mobs to this new point and kill.
Repeat.

Since the bonus RAF stops at 60th.
And you can boost a toon up to 60th.
Account B can grant levels to a toon on Account A.
Account A is doing the boosting.

So say you want to have... druids, shamans, warlocks, priests and hunters.
Account A will boost BCDE with one of each class.
Eventually, you have a level 60 Shaman, Warlock, Priest and Hunter on each of BCDE.

E can give D... 28 levels per level 60 toon, so 112 levels.
D can give C.. 112 levels too.
C can give B.. 112 levels too.
B can give A.. 112 levels too.

But, because:
E gave 112 levels to D, D has 56 additional levels to grant to C.
D gave 112 levels to C, C has 56 additional levels to grant to B.
C gave 112 levels to B, B has 56 additional levels to grant to A.

And because:
D granted 56 additional levels to C, C can grant 28 extra levels to B.
C granted 56 additional levels to B, B can grant 28 extra levels to A.

And again:
B received 28 extra levels from C, they have 14 more to give to A.

So in all, A will receive from B... 112 + 56 + 28 + 14 = 210 levels.

Now we have sets of Druids, Shamans, Warlocks, Priests and Hunters on B-E.
A doesn't have any of these, and you want to 5 box each combination.
Since there are 5 classes and you have 210 levels...
210/5 = 42... or 210/4 = 52...

If you have none of the classes you want to end up with on A already...
You can level 5 toons to 18th level (and 90+ into the level) and then boost them 42 levels each.
You could level 4 toons to 8th level each (and 90+% into the level) and then boost them 52 levels each.
The toons end up at 60th and the same percentage into their levels.





If you don't have any existing toons on account A...
Example brand new server, or opposite faction.

You set up the accounts the same way.
A -- B -- C -- D -- E
So the levels can be cascade granted backwards.

If possible have a friend boost you.
A bit of gold loaned could help enormously.

On a brand new server, you'll pretty much only buy essential spells.
Shaman's will go with Lightning Bolt, Lesser Healing Wave and maybe a totem per toon.
Mana Spring, Flametongue and maybe Wrath of Air. Water Shield helps too.
As you level up, especially 60+, gold becomes a lot easier.
You can go back and buy anything relevant for your spec.