No, it isnt.

And we must make a difference between guerilla warfare and terrorism. Guerilla warfare, like a group fighting an occupying power, can be effective.

Terrorism is the targeting of civilians for political purposes, and to spread terror.

Terrorism generally turns a population against you. Take Islamic terrorism. It has generally turned the West against muslims, and served as fuel for anti-muslim sentiment. Now since many Islamic extremists actually do want to increase anti-muslim sentiment in the west for propaganda purposes, they could technically be used to say terrorism works. However at getting sympathy for muslims, terrorism has failed. It fails to get sympathy for causes.

Another one is generally Palestinian terrorism. Palestinian terrorism during the Second Intifada has generally lurched Israel to the right, and is partially responsible for the election of Netanyahu and his Likud party. It has only set back a lot of sympathy the israeli electorate used to have for a Palestinian state.