The reddit user KatNine has started doing a few editorial entries on Shadowrun and how to get into it. They have generally been quite good and a nice little insight for players outside of the game.
The advice in the first post is sound, focusing on how to tackle moving from easy to run characters to the more complex ones. Another way to tackle this with experience rpg players is to deligate learning the rules to people. This takes some of the burden off a GM but means you have to rely on the player to be playing correctly. Best to skim over at east once
Shadowrun is a semi-complex game, it involves at least three overlapping "worlds". You have the Mundane that everyone interacts with. You have the Matrix which technically everyone interacts with but functionally only a few really thrive. Then you have the Magic world that are the Awakened's domains.