r/bindingofisaac

So I bought it a few weeks ago for the switch and really like the game. Mom and mom's heart are no problem but then the steuggle begins..

Killing Isaac is something I can manage in like 60% of the runs I try but satan.. it's almost only possible for me with Azazel and even there only when I have like 8 hearts or more.

Hush? I defeted once with Azazel and that's all..

Also I know that after Satan/Isaac there is more (like mega satan) but I don't know how to unlock it. Placing bombs next to Angels in Angel rooms doesn't trigger them to attack me. So I guess I have to unlock it first. Is this something easily unlockable ir do I have to google how to unlock this? PLEASE DON'T SPOILER ME ON THAT, JUST GIVE ME A HINT!

So how you guys managed to get so "good" in this game? Is it only skill or are there some (item-) tactics I should know?