If your cabling gets too in the way of itself don't be afraid to unplug everything and start over.

If it won't post, reset your RAM by removing it and putting it back in again.

Nothing should be difficult to insert/plug in. The RAM and video card probably has the most resistance because of their long connections, but it should never feel like you are struggling to make it go in. That is a good sign that something isn't lined up properly or isn't the right connection.

I typically will install the cpu, RAM, and possibly cooler depending on size and space outside of the case then install as one unit just because it's easier. I don't bother with a grounding strap and build on a wooden desk or table on carpet and haven't ever had an issue, but ymmv.

I think the biggest thing is thinking through your cable management and routing to avoid redoing work and getting a clean build.

As for screws, it depends but I go for good and snug with a driver for everything that isn't knurled. I don't wrench down on them, but in a few areas finger tight may not be enough (or will lead to vibrations and rattling). Fans, radiators, PSU, and cooler screws all get snugged. Fans especially I've found can be tough to drive if they aren't pre-threaded (and most don't seem to be), the screw cutting threads in the plastic as you drive it means you can't go "finger tight".

If you build it barefoot, you should mostly be fine static wise, just keep touching the case.

Remember to put things like m.2 drives in before big heat sinks/ GPUs go over the top.

The fucking io shield, make sure none of its little tabs are sticking into any ports.

Don't mix power supply cables.

Remember to take the cover off the heatsink cold plate.

Also don't rush it. True for most similar tasks. You can always take a break and maybe you should!

Zip ties (or other things to tie cables together) are your friend. It helps with cable management a lot. Also, it's typical for cases to have spaces for wiring to go "behind" the motherboard so the wiring isn't allover the place inside the case.

Take your time and read the wiring instructions. In most cases you can't screw up, but some of the indicator lights/usb plugs can be interchangeable.

Don't forget the thermal paste!!!

These probably aren't new tips depending how many "years" since your last build, but good reminders anyway:

nvme SSDs should be installed with one end on a stand off of some kind (this will be preinstalled on the board 99% of the time) so that it is parallel to the motherboard when it's plugged in and secured down. The SSD should not be angled downward.

If you're not using every RAM slot, make sure to check which slots to use (usually the 2nd and 4th slots counting from closest to furthest from the CPU)

Make sure to check that the appropriate standoffs for your size of motherboard are installed and no extras are in place.

If you aren’t totally sure and it’s been a while, put everything together on the motherboard box first. Make sure it works. Then reassemble it all inside the case. Makes it easier to address issues.

Cable management only after you’re sure everything works 🙃

For normal fans, the air flows towards the side of the grille.

If your motherboard comes with a separate IO shield, install that in the case as the very very first thing you do. Many mobos come with them permanently attached these days but some don't.

Be very careful with the USB plugs, they can be kind of fragile.

Many CPU coolers come with a protective sticker over their contact patch. Remove this.

I usually like grounding myself with the wrist strap anyway :3.. when im handling something over a grand there isn't a level that feels too careful

I think you got most of it listed tho