When the postie comes, I'll be building a PC for the first time in years. What are the do's, don'ts and tips nowadays?
Obviously classics like RTFM, plan ahead and retrieve any dropped screws are evergreen.
Things I believe are true: tighten your CPU cooler screws evenly (like putting on a car tyre), all screws should be no more than finger tight, build in a dust-free environment.
What about grounding yourself? I remember reading that the danger of this was way overstated and e.g. anti-static wrist straps were a waste of money. Is building in a case that's plugged in (but powered off) enough?
I've seen recommendations to build outside of the case first to test components - is this good advice?
Anything else?
As far as grounding yourself, I'd say just touch the screw on a light switch or similar grounding point to discharge prior to building. As long as you aren't shuffling around on carpet or anything, you should be fine. (protip: grab the shaft of a screwdriver or other metal object and touch the grounding point so you don't shock yourself with the arc.)
You can build outside of the case first if you want, and probably would be wise if you're using used components. Make sure to set the motherboard on top of its anti-static bag to avoid unintentional grounding.
As far as screws go, I screw them in finger tight, then use a screwdriver to torque them about another 1/4 turn.
More like pro tip: Touch the exposed metal parts of the case at all times.
If the air is dry enough, it is trivial to build up enough static charge between a light switch and what ever working area the PC is being built in.
Also always touch a large metal sink of a component first, and touch both parts that are to be brought together. Heatsink, pci bracket, what ever, just get the charges equalized before plugging, or any charge difference is going to go through data lines instead.