Ignore them. The only way to get better at tanking is to try your best and imporve on mistakes you think you made. One trick you can do is pull, tab, fast blade, tab, savage blade, tab, halone while weaving flashes in the combo every 10 or so seconds to ensure maximum enmity. If you have that guy not attacking your marked target, let them tank the one they choose to focus. Its their own damn fault.