My two recommendations with Fabled , if you want to improve on consistency:
Try and add more cards that let you continually discard - Gates of the Dark World would be my choice. Gives your monsters a +300, lets you discard one card a turn and get a draw for it. I'd also advise replacing Dark Core with Dark Smog - it lasts longer AND works on your opponents turn
Work on the monster/discard cards outlet - occasionally, you have hands full of one with none of the other. Things like Dragged Down, Dark World Dealings maxed (Although I think you already run 3?) and cards like it let you discard one AND draw one, so you have a discard outlet and a draw in one.
As for overextending, try to keep some cards in your hand at all times. Cards that I mentioned before, like dragged down and DWD let you draw for each discard, so they keep your hand full. Things like Dark core need you to lose 2 cards (-2) for you, to banish 1 monster (-1 for your opponent), so ultimately, you end up losing more. Also, try not to summon too many monsters to the field in one go, because a well timed torrential or bottomless could wreck your plan and leave you with an empty hand - maybe only go for one monster if your opponent has a lot of backrow - Ganashia at 1800 can be a good beater early game.