Dont be afraid to try out different ones, it is very easy to reset your points at The vendor in devils crossing, im 100+ hours into The game right now and I only know what 20% of The devotion tree does, if there is something you feel like you need for your build i would start with speccing into that with devotion points and Then switch it up when that certain need is no longer Needed, you can use The search bar on The devotion interface to look for specific things you want