The invader can come every 25 motes just keep an eye on the board and watch your back. Like he said know where the invader has a possibility of spawning at and stay out of those lanes when you have a possibility of invasion. All of those positions can be flanked, what i find also helps is to not be so bunched up when you get invaded so the invader has to move more to get kills. I've walked right up on tons of invaders just sitting in their sights and not even noticing me