Whoops, I missed n0nce's reply.
* Don't create channel between 2 already connected nodes. (e.g. check via LN explorers)
That's exactly what I had been avoiding until I made a mistake. I opened a channel to both Bitfinex and Nicehash. I had been routing fairly large payments between those two channels until Bitfinex bumped their fee rate from 1 ppm to 100 ppm. While I was trying to figure it out, I learnt that Nicehash and Bitfinex have had a channel for quite some time. It looks like my node was routing payments between them whenever their channel was unbalanced. I still keep those two channels open because I keep routing payments through them from/to other channels.
* If a channel starts to get used much, but only in one direction, rebalance it so it continues being used.
It might sound easy, but it's a huge pain in practice. I mostly use
ZigZag.io and
Boltz for non-dual-funded channels. When I was running LND node, I tried
Loop but it failed 90% of the time. Since I have a couple of active channels, I might try circular rebalance soon. Also, it makes sense to wait a couple of days and see if the channel will balance itself.