Well seeing as everything is interwoven. It´s not as easy as it sounds.
Stopping the "false flag" terror attacks (9/11?) which are used to invade other countries or start wars. The "gulf of tonkin" event, 9/11? and now N.Korean apparent sub attack. To name a few major events. Would be a good first step.
As for the "islamic" terrorist, your gonna have to ban the religon and wipe these lot out to totally get rid of it, and this act would of course cause a backlash and lots of bloodshed.
There will always be some minority (or majority!!) which arn´t happy with the way things are going, and who might resort to violence.
For example if the world banks decided to take over everything and squash the average person like a grape with financial pressure, internment camps and SS style police. And these "average" people got a bit upset and decided to kick ass, then would you support attacking these "Terrorists".
The word "Terrorist" is used too often nowadays, as a branding iron to make an excuse for attacking certain groups.
Anther problem is certain "terrorist" states are tolerated othes are not, take Israel for example, what they are doing and are allowed to get away with is beyond belief imo.