The can opener and the elbow dig are the two best ones for beginners, because they are so effective for minimal skill, but here's something a little better.
Just lock your opponent down by pushing your palms into your opponents ribs, keeping your elbows in and maintaining good posture.
Then, slide one of your knees under your opponent's butt and step backwards (like 90 degrees from your opponent) with one of your legs (your foot should be on the ground and your leg should be extended, and your butt should be off the ground). Then take off the arm that is on the same side of your opponent and pop the guard by dropping your hipsbackwards (this is the direction 45 degrees from the was your leg is pointing, so, perpendicular to your opponent). This should open the guard.
Once you have opened the guard, go about your pass whichever way you like to pass (toreando, double under, spin pass or shoulder pass or whatever).
If you need help with the actually passes and not just the breaks, Fedor>all, let me know.
Thanks IronMan, it's mainly breaking the guard itself which poses problems for me. I'm pretty explosive when it comes to actually passing, but I really needed to figure out more ways to open the guard. I'm going to re-read what you typed up and try to visualize it, thanks for your help man, it's greatly appreciated!