The bullet-point summary:
  • reachability - make sure nodes can connect to yours
  • latency. Tor seems to be problematic. People like @DarthCoin have written extensively about this
  • interconnectedness - open channels with people! the less hops the better
  • liquidity - seems to be more complex than just "more sats", will be covered in a separate piece

We have to face reality; Lightning Network doesn't yet allow the same level of reliability as current payment systems or Bitcoin on-chain payments. It is still pretty common to experience failed, or unusually long, payments.
It's good to be realistic.