I understand that the difference between 「見る」 and 「観る」 are similar to "look at" and "watch". That is, the first one is more like feeling and judging things by eyes, while the latter one is more like looking things with more attention.
However, 「観る」 is not included in the list of daily used Kanji. That is, 「観る」 is not officially recognised to be read as "みる". So, it is safer to use 「見る」 if you do not know which one to be chosen.