The direct thing we can do to prevent "homegrown" is have a nationwide effort to address minority communities that have some conclave sense of loyalty where stuff like this breeds and their religious places. I've thought whether a religious council for the country to discuss such issues would be beneficial. They need to be reading from a "hymn sheet" of not isolated communities but being a part of the country's community, whatever skin colour or religious beliefs.
Then the Middle East - the root of all the issue needs to be addressed. ISIS clearly need wiping off the face of the Earth and then they clearly need STRONG leaders. Any typical democratic, suit wearing politician aint gonna last there. If it means iron fist rulers like Assad maybe that's what's necessary as they are so religious it only takes one to want to manipulate that for their own gain and it's not so hard when things aren't going well in the country. If people like Assad are necessary, we need to have the necessary agreements and checks in place to make sure they don't abuse their power. Education in the middle east is a huge must as well. It used to be the centre of academic excellence in the world and it'd take a huge concerted effort to get it moving back in that direction but it needs to be done and it can be done. The only problem is the Middle East is seen as some sort of sand pit for companies to make shit loads of money like there aren't real lives suffering because of it.