I would never have known this as a newer developer. What are methods or components I should use and vice versa - avoid? Are there any hints or signs I can be aware of to avoid bad performance?
That comment isn’t actually networking related. There’s a lot of threads on the forum about reducing or avoiding the creation of garbage. It is a pretty big topic on its own.
On actual network performance…
Avoid sending updates to clients for information the client doesn’t need to know. Avoid sending updates to clients more frequently than necessary.