It takes experience to get good, there really is no good site with pics AND descriptions to study. Probably because there are just too many morphs and combos now with some having little if anything different enough to see let alone describe. I'm just happy to have a reference like the genetic wizard to at least show some pictures of many of the morphs and combos. It still has a lot of blanks but it's the best I've found. Other than studying pictures, experience is going to be your best bet to get good at IDing. Nobody knows them all and even the pros have to make their best guess on some so you just need to put the time in and as you get more experienced you'll get better at IDing.