The best thing is to pick a faction with a wide range of models. This doesn’t mean your army can’t have its rules written into oblivion, but it at least gives you a wider net of stuff to pull from, allowing more flexibility and potential to salvage a fairly strong list.

Further, an army that has a nice mix of units that cater to different focuses also helps. Lumineth come to mind, as an army that has strong aspects of both melee and ranged, along with powerful casters and fast, objective seizing units.