There are 14 Echoes not including DLC. If you can average 2 per echo, you'll get this achievement no problem. On average, you need between 3,000 and 7,000 skillpoints to get 2 stars in these Echoes. Change out your guns frequently and try to capture all the easy (for you) skillshots to maximize your score. Don't forget to kill the Electrofly swarms, as that's an easy 500 points.