For jinteki - beyond "not getting mad," really just a "gl, HF" at the beginning and a "GG" at the end are most of what you need. If you need to make any manual adjustments (adding counters, pulling a card back from the heap, whatever) just check in with the chat box first.
For in person, some of the not-so-obvious things that I find helpful: Not too many people do this, but I like it when people (and I try to do this myself) splay their credits like a bank teller any time they are cashing in for a larger denomination. Also, announcing your actions out loud by click number (e.g. "Click 1: Jackson," "Click 2: Install," etc.) helps both players keep track.