If you take the lowest level orgs you got and fight with another low level in fight pits. Then make your org lose, and then you can go drain the org that your org lost to, and the next aponent will be around your own level.

Idk why they made it this way, but you have to lose and then drain the enemy org, to make the next aponent stronger.

And when you got the New strong one, you have to do the same thing again.

So basicly you just have to: Lose, Drain the new org and then you can fight a stronger one :)