Interesting question and I think if I were to try and make money as a LN service provider, I'd consider this a trade secret. Since I'm not and with little experience, the most I can do here is help generate ideas for you, so I don't mind spitballing.

I would try to gather as much info about the network as possible, make some initial test channels at low non-zero fee and come up with an adaptive algorithm that sees where fees are coming from and adds liquidity to chase and support the nodes generating those fees. I guess everyone else will be doing this as well so opportunities might be short-term and have more to do with predicting future flows than standard rent-seeking kind of behavior.

I'd imagine reputation weighs heavily as well so I'd want to ensure 100% uptime as I do all of the above so payments routed through me never fail.