Help with better map awareness?

Let me tell you a story of my second ever ranked game yesterday.

(Me): Le farming in top lane, LvL 8 by this time.

dies

"Shen no ult?"

"Sorry, didn't see."

"Omg"

le dies again

"WTF NOOB SHEN DONT PICK SHEN IF YOU CANT ULT"

((The second time he died I had clicked on him to ult, and he died before it went off.))

"I did ult you. You died before it activated.

"Yeah right"

[All]: "Report Shen unskilled can't ult for shit. Useless as fuck."

20 minutes in, teamfight in mid.

Guess which slime died again. And blamed me for not ulting.

"SHEN. YOU WERE DOING FINE WITH YOUR ULTS A MINUTE AGO. WTF"

"There were like four people there, If I ulted you they wouldve gotten a double.

"STFU NOOB"

Le end of story.

I know this Zac is toxic af and deserved me to not ult him. (Actually I didn't ult him a few times on purpose for that reason. Didn't say a thing those times though*) But there were times, especially in the beggining where I felt so bad about letting my team die because I didn't see anything important happening. I was more focused on farm, which, come to think of it. The Zac complained about my cs too.

"Noob Shen only 98 cs @ 20"

This could be bad for all I know but the main focus of this thread, how can I better my map awareness, since I really want to main