1st crossova.
One of the easiest things you'll do, but if you do it right, your D won't know what hit him. What you do is first you do a one handed crossova (take the ball in your right hand, cup the ball while crossing your right arm across your body. Now your palm should be facing down because you turned it, so then you bounce/dribble it back to your right side. Note: there is only one dribble in the one-handed cross, and it goes fast so there is no need to be able to hold the ball across your body in the air for any amount of time). The trick to this is that when you bring the ball to your left side (across your body) your left hand will be moving right and cross overtop of the right hand. When your bring the ball back to the right, the left hand moves to the left. The D will see your two hands moving different directions and not know which way to go.

2nd Crossova (Cross of Doom)
All you do is 5 easy steps:

1) Ball in bad hand (left for me), fake dribble to the left.
2) Pretending like you think that you faked out the D, cross left to right with your left hand dribbling to your right hand.
3 (Optional step)) Dribble the ball with your right hand thru your right leg by lifting up your right leg. You should now have the ball in your right hand.
4) Do a spin dribble, spinning clockwise (right shoulder going backwards) so your facing the left of your D.
5) Last move: Cross hard to the left with your left hand.

Go try em out. You will be pleasently surprised.