You're pretty decent :D
What you need to work on:
-Champion name pronunciations (Lucian = Loo - Shen, it was arguable on release, but almost everyone says Loo - Shen now.)
-Champion spell names (A lot of shoutcasters memorize the names of the spells, so that they don't sound silly when trying to remind Zilean's W's name)
-The fact that you give information is nice, but it's not something you need to linger around. There are some times when you were talking about something that wasn't necessarily related to the event happening. Try to stay on topic, bud. :)
Keep practicing!
I would recommend watching some other people who shoutcast as well, such as Jump in the Pack or Protatomonster*.
Jump In The Pack: https://www.youtube.com/channel/UCPOm2V7Ccdlkm2J1TqNptEw
Protatomonster: https://www.youtube.com/channel/UClh5azhOaKzdlThQFgoq-tw
*I am not associated with these people in anyway