Try moving around when you're hacking - think about how you can get out of sight, or make yourself less of a target behind shooty friends. Also, wait for waves of your team to get proper support. When you all arrive try to dive in and hack for a bit, then if it's just you left/if you become a target, stop hacking, clean up the enemies or wait till it's safe, then start hacking again. They're my tactics! And try to kill those pesky engineers first!
Sorry if this post is no use :shakehead: