Tip 3: win on time
It took me a while to learn that part of the etiquette of online chess is that when you are winning on time, you take the win. It might feel somewhat shameful to win by shuffling pieces back and forth in an opposite-coloured bishop ending in which you have an extra five seconds, but that is what it takes. Everybody else will do it to you, and it seems to be accepted among strong players that time is just as important as any other aspect of blitz chess, no matter how frustrating losing on time can be.
Exhibit A: GM Henrik Danielsen in a live blitz game on Youtube. Sadly, he doesn't make these videos any more, but there are about 100 of them and they are by far the best chess videos I have ever seen. If you search through Danielsen's videos, you'll see plenty of examples of him ruthlessly winning on time against strong players.
When I first started playing online chess on FICS, I used to offer a draw if my opponent had played a good game and was losing in time in a winning position. Let's just say that watching these videos cured me of being a gentlefish for good!