What do you have? Chiara, Redra, Praxie make a good start to a half deck. After that it kinda comes down to what you want/need.
I personally pair up Skeelz and Sentinel when I'm really scard of SoA. It is possible to build a Sentinel deck that fares well against SoA, but it really requires some expensive cards and tough choices.
The problem with sentinel half decks is that a lot of their staple elo cards like Coby and John are not quite as effective in the half decks. I find it hard to run an effective sentinel half deck but if you can manage it, then by all mean, go ahead.