ok there is a huge area of improvement needed.
First off, you really do need better micro, but that comes with practise.
First off, items. in beginign dont use lightning shield on creeps. I noticed u put lightning shield on a creep and ur fiend recieved all the damage from it. Lightning shield is ment to damage all the units around a unit. It is good for units taht jsut tp'ed or units that clump like fiends and archers.
although when u did it you didn't really need the gold. you expanded 13 minutes into the game try and make it faster. Also, gold that piles up is gold that is wasted. Unless you have a specific strat in which thsi is needed, spend ur gold. buy items, upgrade and build zigs. I noticed u had a minimul amout of zigs. Also do not upgrade all your zigs, that is uneccisary and is a waste of gold.
Building placement is your friend. you building layout is rather... well to be honest it is crap. key placement of zigs u want to be spirit towers is essential, you don't want all your buildings to stick out, u want to keep it pretty close, so ranged cant pick of buildings than run. There is also that cramped base where u tp and u get picked off. you can aim your tp. so jsut keep a spot in your base open so you can move in on your opponent inf the need arises.
there was no need for you to have lost your DK when u attacked his base. he should have either been given a potion, or stayed in back gathered exp and let statues heal him.
Also, your tp is one of the most important things u have. I noticed u used a tp to get back to your base. Taht is not good. Run your untis back. 350 gold is not to be wasted so easily.
And if you say that he won because he was undead I ask you. was it not the NE who ran his army into his base to get his units blasted by the spirit towers? or that he sent a lone chim to attack after he was defeated. or that he didnt tp when he started to lose units? lets not forget the lack of scouting by both parties. this game had errors on both sides.