There can be many more additions to this list. I am just citing the main aspects from the top of my head.
1. We should always remember (whenever we do anything really, not just when we sit online) that Allah SWT is All-Seeing, All-Knowing. The Holy Quran says,
"But verily over you (are appointed angels) to protect you,- 11. Kind and honourable,- Writing down (your deeds): 12. They know (and understand) all that ye do. 13. As for the Righteous, they will be in bliss; 14. And the Wicked – they will be in the Fire, 15. Which they will enter on the Day of Judgment "
( Holy Quran : Chapter 82 : verses 10 -15 ) Al-Infitar (The Cleaving, Bursting Apart)
"Behold, two (guardian angels) appointed to learn (his doings) learn (and noted them), one sitting on the right and one on the left. . Not a word does he utter but there is a sentinel by him, ready (to note it)."
( Holy Quran : chapter 50 : verses 17-18 ) Qaf ((the Letter), ( Q ))
- keep the conversation/tweet/post/email/chat as short as possible
- use a minimum of emoticons in your speech
- appear as strict as possible, so that no 'possibilities' arise in anybody's mind
- involve others in the conversation (like, maybe ask your parent for some advice when they're passing by etc)
- 'blind' chats
- anonymous emails
- 'secret admirers'
- online declarations of love and all that follows (without the parents having the slightest idea what the kids are upto and why they spend so much time online).