First technique to getting life back on track: make it a point to ask yourself as often in the daytime, "Is what I'm currently doing beneficial to my overall goals?"
It may be better to hone which goal(s) in particular you want to work towards. If your goal is to succeed in an exceedingly difficult major [that is way out of your league and you're probably going to lose $1000 worth of an investment in and probably going to be homeless at some point... but I digress], then scavenging for pics of awesome chest tattoos or researching the history of the Iron Chef series is highly irrelevant and a waste of time. Granted, very captivating, but time management's about choosing the activities for every area of your life, including your free time, wisely (you could've been taking a nap to prep for the all-nighter you'd pull later on that day.)
And if the action's unproductive, resist the urge to say, "fuck it, I'm doing it anyway, it's not gonna take that long." Just don't even let that phrase be a part of your vocab.
Plus, you'll feel more in control of your life, which I know is a problem for peeps like me. So try it bitches!