PredatorFollow

Hi, kinda new,level 33 Assassin, and was wondering what would be the best tree to go down on the predator sheet. I have about 12 points to spend but can't decide. I put 8 on agility, the second tier, cause i thought agility would help but my friend says its a waste of time, so now im thinking strength tree which has one on their. I also heard to just stick to one tree and then move onto the other page with your skills. Thanks for whoever can help me.