Well, after more than a week of juicing I  have learned a few things.
1)  You can mix almost anything together...there are no real rules.  But apples make everything taste good.
2)  The juicer we bought (Breville Juice Fountain) is great for most things but not leafy greens.  I have a way to increase the amount of nutrient-rich green juice you get from Kale and other leafys.  I put them in the Vitamix with some water (not a lot of water-about half way up the pitcher full of greens) and blend until smooth.  Then I filter them through a mesh strainer and voila!  Much more product than from the juicer and fantastic taste. 
3)  I can go a LONG time on juice without feeling hungry.  Much longer than on food.  Amazing.