OK, this is probably going to sound REALLY stupid, but I agree with Rudyard Kipling: only God can make a tree... so I let Him do the creating and I adjust for scale...
I like to take pieces of azalea or crepe myrtle with a somewhat straight branch that can be used as a trunk, and look for fairly symmetrical offshoots. I remove any leaves, leaflets, and buds, and attach some model railroading foam foliage with a little white glue to simulate leaves, and I'm done. Since everything is natural, I don't have to paint to get a realistic result. Hope this helps.
Gip Winecoff