[Hana]

As far as battle strategies go using a combination of illithids (I prefer the cheaper ones that are less resource intensive and only use mind bLasts) and shambler thralls and/or lobo guards seems to work wonders on most armies. Just be sure to protect the illithids with other (preferably mindless) units.

If you plan on using the void gate frequently then be sure to use Starspawn priests to do the summonings. Since they sometimes get attacked (by both the monsters they may summon and an occassional horror) you may want to arm them with a few items, or better yet set their battle orders to retreat, though I'm not sure if you can retreat from a botched void gate summoning. A magically strong pretender might be in order as well, since most if not all of the void gate summons I've seen are sacred troops. I'd also recommend periodically assigning a different priest to void gate duty. That way if one goes insane or dies from an attack you'll have another priest with a decent summoning skill.