Some guidelines:
1) Change your targeting to reduce fraud clicks. As an example, you can choose to target only users of your audience who use Gmail. In the U.S. at least, this works because Google makes it very difficult to set up fake accounts in mass due to phone verification. There are many other targeting options as well that will significantly reduce fraud.
2) Always use the hack mentioned by adambratt. Your posts will show much more ROI when there is social proof.
3) Focus on post quality and virality. Posts that have low interactions are just going to be difficult to show any sort of ROI. The power of Facebook is when you combine the organic WITH the paid reach. The paid helps you initially get in front of the appropriate audience, and then when your post is shared and liked it will organically show up in the newsfeed of their friends and followers. This is where the the true power of Facebook advertising lies.
Now personally, I've seen much more ROI with Google than with Facebook. Search/purchase intent is the differentiator: visitors are coming to your site with a goal in mind. With Facebook ads, however, I've run campaigns where 70% or more of the incoming traffic bounces within a few seconds. In my experience it's much more difficult to get quality traffic from FB, but far from impossible.