User blog comment:Arkxiah/These summons recently/@comment-29698706-20170610154751

Only summon from gates that have some kind of promise to get an Omni no matter what, rahter that's an Omni only gate or if new units you like come with a 10+1 gate where you know you're going to get one of the featured units after 10 summons. Limited Edition Summons usually aren't too bad either, even if you don't get the target unit it's more Omnis than not and you get high grade Elgifs every 6 summons.

Since you're clearly on this wiki, make sure to check new units to see if you'd even want to summon for them in the first place too. You've probably not been trying the right gates if you're having that hard of a time avoiding the non-Omnis.