Well I have been playing a few games now and I have been focusing solely on my macro. There has been a few times where it has slipped due to early pushes though but it is getting better. However, when my pure macro goes good then I feel like I cant lose because after every engagement I have a fresh army ready to go again
Still in Silver League atm but I just destroyed a Gold league "slightly favoured" Terran player with an Infestor/Zergling/Ultralisk combo with a few muta's to deal with drops and reached Rank 1 in Silver so improvements are definitely happening! Which is evident by my match history: http://i.imgur.com/izkfHDs.jpg
One thing I am still unsure of as Zerg though, in particular against Protoss but also in general which is when is it safe to take and 3rd and 4th etc? I lost a game earlier to a Protoss player and I feel that I got too greedy and took a 3rd so my army just couldn't handle his Colossus/Stalker/Charge Zealot force. Against a passive Terran player I try to take a 3rd around 7 mins or so but against this Protoss I took a 3rd at 8 mins so I am not sure if i was just being greedy but it could also be a combination of that and that I didn't scout as much as I perhaps should of.