Question: when you don't get a tower on the first turn, or in any other case where you can't play a card on the first 2-3 turns (this happens way to often with this deck btw) what is the best choice of card for the discard at the end of your turn? It's really bothering me it's like having to give away one of my children!!!
Heals are thoroughly expendable, but aside from that, it's quite situational. If you're loaded with CC, drop a CC card. If you're loaded with PC, drop a PC card. If you have a bunch of high-damage creatures, drop one of those. Also, don't forget to take into account what you've seen of your opponent, though it's not always easy to tell exactly what you're fighting in the first turn or two, but (for example) if you see something that looks like a mono aether, you might want to keep your PC and discard a creature
even if you're heavy on PC.
Basically (while factoring in as much information as you can), discard whatever you've got too much of.
(And I realize this is probably less of a detailed answer than you were going for, but there's not really a way to prioritize what cards to get rid of, as it depends greatly on the details of the specific situation.)