If you want to be completely independent chose individual shards and stick with the most popular shards. If you dont mind asking for help here and there. Pick nothing but ATL shields and send the tokens out with people so you can transfer back to atl.
Personally i have been working on having every shard so i can operate completely independent.
However here is a simple way for you to choose.
Reasons to cross shard
Idocs - Go see how many idocs you can find and if its worth it for you to be there.
EM events - See which EMs you like, personally i chose EMs that are very vocal about who, what, when and where. and update the days of events as early as possible.
Merchandise merchant - certain shards sell items for less than atl. Buying on one shard to sell on atl has become a thing.
PvP - Now with this one its kind of tricky. I have a pvper on almost every shard now because of the "hot spot" trend. Seems like every 6 months there is a "new awesome shard for pvp"
General Population - Get in gen chat and talk with some of the locals. perhaps meet a new friend.
Artie farming - Finding a dead shard to do champ spawns, find legendaries, mine... etc. etc... if you are in to that thing... find one you dont lag on and no one bothers you.
Each one scores a point. shards with the most points are the ones you pick.
Go hang out on each shard you are thinking about and weigh them in.