1) Limit your disclosure on the forums. This isn't to protect us, it's to protect you. Lawyers do mine online forums for data on accidents, and can even identify if they have found their opponent if you disclose enough information. This has happened at some of the car forums and it has cost members settlements that are satisfactory.
2) See 1 and drive it into your brain.
3) See 1 and 2.
4) This actually applies to any potential legal action, whether you are cycling, walking, or driving a vehicle, or even a workplace accident. In a nutshell, you do not want to disclose a tremendous amount of specific information when you are potentially going to have to sue someone to anyone but YOUR lawyer. He or she is being paid to and is ethically bound to represent your interests, and the other lawyer is paid to, and is ethically bound to represent theirs. Don't make THEIR job easier and your lawyer's harder.