Rig is moving other parts of my mesh for no reason! I've been following this tutorial to rig my blender character https://www.youtube.com/watch?v=mhQY2_gVoVg and no matter what I do, my rig moves other random parts of my model. If I move one leg, the other leg follows? Something's also wrong with the hands.  I've applied the mirror modifier, parented using automatic weights, I even removed the mirror modifier, duplicated the half of my model, mirrored it, then joined the two so there would be no need for a mirror modifier. No matter what I do, my rig seems to be acting up strangely. I even play around with the weight paints, but it still doesn't work! I'm assuming there's nothing wrong with my mesh and that it's something with the rig, but I don't know what. Please help!
In Object mode apply the rotation and scale of your object with ctrlA, then in Edit mode recalculate the normals with ctrlN.

Also maybe remove the doubles, put the Armature modifier above the Subsurf, enable the Preserve Volume of the Armature modifier, join the fingers to the hands, etc...

Anyway it will need some corrections in Weight Paint mode or with the Vertex Groups Assign button.