My top tip would be to signal. Lots. Whether or not you think there's another bike behind you. Each year there's more and more people cycling and I've avoided a couple of probably-annoying shunts because someone unseen shouted when I signalled
Second is to signal even when passing oncoming cycles in narrow lanes. Ideally to the left. I usually just extend my left hand leftwards, so it doesn't look like a left-turn signal, and that's enough to work.
Clean your drivetrain in winter. Really, really thoroughly. Otherwise it will become unusable terrifyingly quickly. And expensively. It's not the 1980s any more.
Nah. Encase your drivetrain!
Fit spiked tyres if you're riding when there's any chance of ice, too.
If you attach something to your bike or rack and think 'that looks a bit dodgy but it will stay on, I'm not going far', it will fall off.
Oh yes. It's flaming annoying that.
If you notice a nut being loose, it will fall off before you get home.
Also, if you can hear metal-on-metal, find out what nut is loose
before whatever movement it's allowing strips the thread from the bolt.
Pedestrians think shared use bicycle/pedestrian lanes are funny coloured pavements and will wander all over them. If it is marked out as bikes one side and pedestrians the other, more than half the pedestrians will be on the bike side.
Yep (but they're not "shared use bicycle/pedestrian lanes" - they're cycle tracks that people may walk on). When you ride outside a town on quiet roads, walkers will often extend this approach to the entire carriageway. It's often thoughtlessness rather than a desire to be a dick and delay you, so a recognisable bell (a brrring, ding-dong or temple bell, not a shrill pinger) from a respectful distance will often bring a positive response and allow you past.
Not to use the idea of disconnecting brake cables when leaving bike outside a shop as a crude anti-theft idea.
Yeeeeeahh... BTDTGTTS. Instead I now set the shifters to throw the chain (derailleurs) or explode their knees pulling away in top gear (hub gears) because that's only annoying if I forget, rather than lethal.