Welcome to the Stronghold!
Firstly the models you have are a good base to start from. I recommend giving your Ogres Ironfists for defence, with their low Int any defence you can get is great, allowing more of them to attack back.
Next step for you army should be characters, and more maneaters. Both of these are fairly expensive so most players kit-bash standard plastic models to make their own (have a look around the forums for lots of examples). I recommend two more maneaters as well as a butcher and/or bruiser. A character is a must to be your army general, and eventually you'll want a Tyrant or Slaughtermaster to lead your force.
After this how you expand your army is really up to you, I recommend going with the models you like and learn how to use them, luckily nearly everything in the army book is useful. At some point you'll want to build up your regular ogres and Irongut units, around 8 strong each seems to be a useful number.
I'm sure some others out here will have more tips, so good luck, and may the Maw bless your dice!
